Background and Aims: Contaminated duodenoscopes and linear echoendoscopes (DLEs) pose a risk for infectious
outbreaks. To identify DLEs and reprocessing risk factors, we combined the data from the previously published
nationwide cross-sectional PROCESS 1 study (Prevalence of contamination of complex endoscopes in the
Netherlands) with the follow-up PROCESS 2 study.

Methods: We invited all 74 Dutch DLE centers to sample
2 duodenoscopes during PROCESS 1, and all duodenoscopes
as well as linear echoendoscopes during PROCESS 2. The studies took place 1 year after another. Local
staff sampled each DLE at 6 sites according to uniform methods explained by online videos. We used 2 contamination
definitions: (1) any microorganism with
20 colony-forming units (CFU)/20 mL (AM20) and (2) presence
of microorganisms with GI or oral origin, independent of CFU count (MGOs). We assessed the factors of age and
usage by performing an analysis of pooled data of both PROCESS studies; additional factors including reprocessing
characteristics were only recorded in PROCESS 2.

Results: Ninety-seven percent of all Dutch centers (72 of 74; PROCESS 1, 66; PROCESS 2, 61) participated in one
of the studies, sampling 309 duodenoscopes and 64 linear echoendoscopes. In total, 54 (17%) duodenoscopes
and 8 (13%) linear echoendoscopes were contaminated according to the AM20 definition. MGOs were detected
on 47 (15%) duodenoscopes and 9 (14%) linear echoendoscopes. Contamination was not age or usage dependent
(all P values
.27) and was not shown to differ between the reprocessing characteristics (all P values
.01).

Conclusions: In these nationwide studies, we found that DLE contamination was independent of age and usage.
These results suggest that old and heavily used DLEs, if maintained correctly, have a similar risk for contamination
as new DLEs. The prevalence of MGO contamination of w15% was similarly high for duodenoscopes as for linear
echoendoscopes, rendering patients undergoing ERCP and EUS at risk for transmission of microorganisms.

Recent outbreaks of duodenoscope-associated multidrug-resistant organisms (MDROs) have brought attention to the infection risk from procedures performed with duodenoscopes. Prior to these MDRO outbreaks, procedures with duodenoscopes were considered safe and low risk for exogenous infection transmission, provided they were performed in strict accordance with manufacturer instructions for use and multi society reprocessing guidelines.

The attention and efforts of the scientific community, regulatory agencies, and the device industry have deepened our understanding of factors responsible for suboptimal outcomes. These include instrument design, reprocessing practices, and surveillance strategies for detecting patient and instrument colonization. Various investigations have made it clear that current reprocessing methods fail to consistently deliver a pathogen-free instrument.

The magnitude of infection transmission has been underreported due to several factors. These include the types of organisms responsible for infection, clinical signs presenting in sites distant from ERCP inoculation, and long latency from the time of acquisition to infection. Healthcare providers remain hampered by the ill-defined infectious risk innate to
the current instrument design, contradictory information and guidance, and limited evidence-based interventions or reprocessing modifications that reduce risk. Therefore, the objectives of this narrative review included identifying outbreaks described in the peer-reviewed literature and comparing the findings with infections reported elsewhere.

​Search strategies included accessing peer-reviewed articles, governmental databases, abstracts for scientific conferences, and media reports describing outbreaks. This review summarizes current knowledge, highlights gaps in traditional sources of evidence, and explores opportunities to improve our understanding of actual risk and evidence based approaches to mitigate risk.

Objective Single-use duodenoscopes have been recently developed to eliminate risk of infection transmission from contaminated reusable duodenoscopes. We compared performances of single-use and reusable duodenoscopes in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP).
Design Patients with native papilla requiring ERCP were randomised to single-use or reusable duodenoscope. Primary outcome was comparing number of attempts to achieve successful cannulation of desired duct. Secondary outcomes were technical performance that measured duodenoscope manoeuvrability, mechanical-imaging characteristics and ability to perform therapeutic interventions, need for advanced cannulation techniques or cross-over to alternate duodenoscope group to achieve ductal access and adverse events.
Results 98 patients were treated using single-use (n=48) or reusable (n=50) duodenoscopes with >80% graded as low-complexity procedures. While median number of attempts to achieve successful cannulation was significantly lower for single-use cohort (2 vs 5, p=0.013), ease of passage into stomach (p=0.047), image quality (p<0.001), image stability (p<0.001) and air–water button functionality (p<0.001) were significantly worse. There was no significant difference in rate of cannulation, adverse events including mortality (one patient in each group), need to cross-over or need for advanced cannulation techniques to achieve ductal access, between cohorts. On multivariate logistic regression analysis, only duodenoscope type (single-use) was associated with less than six attempts to achieve selective cannulation (p=0.012), when adjusted for patient demographics, procedural complexity and type of intervention.
Conclusion Given the overall safety profile and similar technical performance, single-use duodenoscopes represent an alternative to reusable duodenoscopes for performing low-complexity ERCP procedures in experienced hands

Although endoscopic eradication therapy with radiofrequency ablation (RFA) is effective in most Barrett's Esophagus (BE) patients, some might experience poor healing (PH) and/or poor squamous regeneration (PSR). We aimed to evaluate PH/PSR incidence and treatment outcomes.

METHODS: We included all patients treated with RFA for early BE neoplasia, from a nationwide Dutch registry based on a joint treatment protocol. PH was defined as active inflammatory changes or visible ulcerations >=3 months post-RFA, PSR as <50% squamous regeneration, and treatment success as complete eradication of BE (CE-BE). Results 1,386 patients (median BE C2M5) underwent RFA with baseline low-grade dysplasia (27%), high-grade dysplasia (30%), or early cancer (43%). In all 134 patients with PH (10%), additional time and acid suppression resulted in complete esophageal healing. 67/134 (50%) had normal regeneration with 97% CE-BE. In total, 74 patients had PSR (5%). As compared to patients with normal squamous regeneration, PSR patients had a higher risk for treatment failure (64% versus 2%, RR 27 [95% CI 18-40]) and progression to advanced disease (15% versus <1%, RR 30 [95% CI 12-81]). Higher BMI, longer BE, reflux esophagitis, and <50% squamous regeneration after baseline endoscopic resection were independently associated with PSR in multivariable logistic regression.

CONCLUSIONS In half of the patients with poor healing, additional time and acid suppression may lead to normal squamous regeneration and excellent treatment outcomes. However, if patients experience poor squamous regeneration, the risk for treatment failure and progression to advanced disease is significantly increased with a relative risk of 27 and 30, respectively.

BACKGROUND: With the introduction of the national bowel cancer screening program, the detection of sessile and flat colonic lesions >=20 mm in size, defined as large nonpedunculated colorectal polyps (LNPCPs), has increased. Aim of this study was to examine the quality of endoscopic treatment of LNPCPs in the Dutch screening program.

METHODS: This investigation comprised 2 related, but separate, substudies (one with a cross-sectional design; one with a longitudinal design). The first examined prevalence and characteristics of LNPCPs in data from the national Dutch screening cohort, from February 2014 until January 2017. The second, with screening data from five endoscopy units in the Southern part of the Netherlands from February 2014 until August 2015, examined performance on important quality indicators (technical and clinical successes, recurrence rate, adverse event rate, and surgery referral rate). All patients were part of the national Dutch screening cohort.

RESULTS: In the national cohort, a LNPCP was detected in 8% of participants. Technical and clinical successes decreased with increasing LNPCP size, from 93% and 96% in 20 to 29 mm lesions to 85% and 86% in 30 to 39 mm lesions and to 74% and 81% in >=40 mm lesions (p<0.001; p=0.034). Cumulative recurrence rate at 12 months increased with LNPCP size, from 9% to 22% and 26% in the respective size groups (p=0.095). Adverse event rate was 5%. Overall surgical referral rate for noninvasive LNPCPs was 7%.

CONCLUSIONS: In this performance of 2 substudies, it was shown that quality parameters for endoscopic resection of large polyps in the Dutch screening cohort are not reached, especially in >=30 mm polyps. Endoscopic resection of large polyps could benefit from additional training, quality monitoring, and centralization either within or between centers. Copyright &#xa9; 2021 American Society for Gastrointestinal Endoscopy.

 BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) is a promising technique for removing superficial GI tumors, but ESD is technically difficult. The aims of this study were to establish a clinical score model for grading technically difficult colorectal ESD.
 
METHODS: Data on patients, lesions, and outcomes of colorectal ESD at 2 centers were analyzed. The objective parameter of successful ESD within 60 minutes was set as an endpoint to evaluate the difficulty. Independent predictors of difficulty in the derivation cohort were identified by multiple logistic regression analysis and used to develop a clinical score. We validated the score model in the validation cohort.

RESULTS: The clinical score comprised tumor size of 30 to 50 mm (1 point) or >=50 mm (2 points), at least two-thirds circumference of the lesion (2 points), location in the cecum (1 point), flexure (2 points) or dentate line (1 point), and laterally spreading tumor nongranular lesions (1 point). Areas under the receiver operator characteristic curves for the score model were comparable (derivation [.70] vs internal validation [.69] vs external validation [.69]). The probability of successful ESD within 60 minutes in easy (score = 0), intermediate (score = 1), difficult (score = 2-3), and very difficult (score >=4) categories were 75.0%, 51.3%, 35.6%, and 3.4% in the derivation cohort; 73.3%, 47.9%, 31.8%, and 16.7% in the internal validation cohort; and 79.5%, 66.7%, 43.3%, and 20.0% in the external validation cohort, respectively.

CONCLUSIONS: This clinical score model accurately predicts the probability of successful ESD within 60 minutes and can be applied to grade the technical difficulty before the procedure. 

BACKGROUND AND AIMS: The pocket-creation method (PCM) is a newly developed strategy for colorectal endoscopic submucosal dissection (ESD). However, its superiority over the conventional method (CM) has not been established. The aim of this meta-analysis was to evaluate the efficacy and safety of PCM-ESD compared with CM-ESD for superficial colorectal neoplasms (SCNs).

METHODS: Literature searches were conducted using the Pubmed, Embase, and Cochrane Library databases, and a meta-analysis was performed. The primary outcome was the R0 resection rate, and the secondary outcomes were the en bloc resection rate, dissection speed, procedure time, and adverse event rate.

RESULTS: Five studies (2 randomized controlled trials and 3 retrospective studies) with 1481 patients were included in our meta-analysis. The pooled analysis showed that PCM-ESD achieved a higher R0 resection rate (93.5% vs 78.1%; odds ratio [OR], 3.4; 95% confidence interval [CI], 1.3-8.9; I2 = 58%), a higher en bloc resection rate (99.8% vs 92.8%; OR, 9.9; 95% CI, 2.7-36.2; I2 = 0), a shorter procedure time (minutes) (mean difference [MD], -11.5; 95% CI, -19.9 to -3.1; I2 = 72%), a faster dissection speed (mm2/min) (MD, 3.6; 95% CI, 2.8-4.5; I2 = 0), and a lower overall adverse event rate (4.4% vs 6.6%; OR, 0.6; 95% CI, 0.3-1.0; I2 = 0) compared with CM-ESD.

CONCLUSIONS: This meta-analysis showed that PCM-ESD improves the efficacy and safety compared with CM-ESD for superficial colorectal neoplasms

INTRODUCTION: One-piece endoscopic mucosal resection (EMR) for lesions >15 mm is still unsatisfactory, and attempted 1-piece EMR for lesions >25 mm can increase perforation risk. Therefore, modifications to ensure 1-piece EMR of 15- to 25-mm lesions would be beneficial. The aim of this study was to investigate whether Tip-in EMR, which anchors the snare tip within the submucosal layer, increases en bloc resection for 15- to 25-mm colorectal lesions compared with EMR.

METHODS: In this prospective randomized controlled trial, patients with nonpolypoid colorectal neoplasms of 15-25 mm in size were recruited and randomly assigned in a 1:1 ratio to undergo Tip-in EMR or standard EMR, stratified by age, sex, tumor size category, and tumor location. The primary endpoint was the odds ratio of en bloc resection adjusted by location and size category. Adverse events and procedure time were also evaluated.

RESULTS: We analyzed 41 lesions in the Tip-in EMR group and 41 lesions in the EMR group. En bloc resection was achieved in 37 (90.2%) patients undergoing Tip-in EMR and 30 (73.1%) who had EMR. The adjusted odds ratio of en bloc resection in Tip-in EMR vs EMR was 3.46 (95% confidence interval: 1.06-13.6, P = 0.040). The Tip-in EMR and EMR groups did not differ significantly in adverse event rates (0% vs 4.8%) or median procedure times (7 vs 5 minutes).

DISCUSSION: In this single-center randomized controlled trial, we found that Tip-in EMR significantly improved the en bloc resection rate for nonpolypoid lesions 15-25 mm in size, with no increase in adverse events or procedure time. 

BACKGROUND: Colorectal EMR is an effective, safe, and minimally invasive treatment for large lateral spreading and sessile polyps. The reported high recurrence rate of approximately 20% is however one of the major drawbacks. Several endoscopic interventions have been suggested to reduce recurrence rates. We conducted a systematic review and meta-analysis to assess the efficacy of endoscopic interventions targeting the EMR margin to reduce recurrence rates.

METHODS: We searched in PubMed and Ovid for studies comparing recurrence rates after interventions targeting the EMR margin with standard EMR. The primary outcome was the recurrence rate at the first surveillance colonoscopy (SC1) assessed histologically or macroscopically. For the meta-analysis, risk ratios (RRs) were calculated and pooled using a random effects model. The secondary outcome was post-procedural complication rates.

RESULTS: Six studies with a total of 1335 lesions were included in the meta-analysis. The techniques performed in the intervention group targeting the resection margin were argon plasma coagulation, snare tip soft coagulation, extended EMR, and precutting EMR. The interventions reduced the adenoma recurrence rate with more than 50%, resulting in a pooled RR of 0.37 (95% CI 0.18, 0.76) comparing the intervention group with the control groups. Overall post-procedural complication rates did not increase significantly in the intervention arm (RR 1.30; 95% CI 0.65, 2.58).

CONCLUSION: Interventions targeting the EMR margin decrease recurrence rates and may not result in more complications

Background: Third space endoscopy technique facilitates therapeutic endoscopy in subepithelial space. This study aimed to investigate peroral endoscopic tumor resection (POET) with preserved mucosa technique for upper gastrointestinal tract subepithelial tumors (UGI-SETs) removal.
Methods: Between February 2011 and December 2019, consecutive patients with SETs of esophagus and stomach who underwent POET for enlarging size during follow-up, malignant endoscopic ultrasound features or by patient's request were enrolled. Demographic, endoscopic and pathological data were analyzed retrospectively.
Results: Totally 18 esophageal (mean ± SD age, 55.23 ± 4.15 year-old, 38.89% female) and 30 gastric (52.65 ± 2.43 year-old, 53.33% female) SETs in 47 patients (one with both esophageal and gastric lesions) were resected. The mean (± SD) endoscopic/pathological tumor size, procedure time, en-bloc/complete resection rate, and hospital stays of esophageal and gastric SET patients were 12.36 (± 7.89)/11.86 (± 5.67) and 12.57 (± 6.25)/12.35 (± 5.73) mm, 14.86 (± 6.15) and 38.21 (± 15.29) minutes, 88.89%/94.44% and 86.77%/93.30%, and 4.14 (± 0.21) and 4.17 (± 0.20) days, respectively. The overall complication rate was 18.75%, including 6 self-limited fever and 3 pneumoperitoneum relieved by needle puncture. There was no mortality or recurrence reported with mean follow-up period of 23.74 (± 4.12) months.
Conclusions: POET is a safe and efficient third space endoscopic resection technique for removal of UGI-SETs less than 20 mm. Long term data are warranted to validate these results.

BACKGROUND AND AIM: The long-term outcomes of endoscopic resection for non-ampullary duodenal neuroendocrine tumors are limited. We aimed to clarify it.

METHODS: Consecutive patients with non-ampullary duodenal neuroendocrine tumors endoscopically treated at our institute between January 2005 and June 2020 were included in this retrospective study. En bloc and R0 resection rates and adverse events were evaluated as short-term outcomes of endoscopic resection. The 5-year overall and recurrence-free survival rates of patients after endoscopic resection were calculated as long-term outcomes.
 
RESULTS: Of 34 patients with 34 lesions, 33 patients (97%) underwent endoscopic mucosal resection and one (3%) underwent endoscopic submucosal dissection.  En bloc resection was achieved in 33 lesions (97%). R0 resection was achieved in 20 lesions (59%). The median tumor size was 6 mm (range: 3-13). Thirty-one lesions (91%) and three lesions (9%) were classified as G1 and G2, respectively. Lymphovascular invasion was observed in six lesions (18%). Intraprocedural perforation occurred in four patients (12%) who were conservatively treated with endoscopic closure. All 34 patients were followed up without additional treatment after endoscopic resection, and no recurrence or metastasis developed during the median follow-up period of 3.5 years 47.9 months (range: 9.0-187.1). The 5-year overall survival and recurrence-free survival rates were 87.1% and 100%, respectively.
 
CONCLUSIONS: Endoscopic resection provided a favorable long-term prognosis for patients with non-ampullary duodenal neuroendocrine tumors without lymph node metastasis.

 BACKGROUND AND AIMS: Post-colonoscopy colorectal cancers (PCCRCs) account for up to 50% of colorectal cancers (CRCs) in patients with inflammatory bowel disease (IBD). We investigated characteristics of IBD patients with PCCRC and their survival.

METHODS: We identified IBD patients (ulcerative colitis [UC] and Crohn's Disease [CD]) diagnosed with CRC from 1995 to 2015. We defined PCCRC as diagnosed between 6 and 36 months, and detected CRC (dCRC) as diagnosed within 6 months after colonoscopy. We computed prevalence ratios (PRs) comparing PCCRC vs. dCRC and followed patients from the diagnosis of PCCRC/dCRC until death, emigration, or study end. Mortality was compared using Cox proportional hazards regression models adjusted for sex, age, year of CRC diagnosis, and stage. The main analyses focused on patients with UC.

RESULTS: Among 23,738 UC patients undergoing colonoscopy, we identified 352 patients with CRC, of whom 103 (29%) had PCCRC. Compared with dCRC, PCCRC was associated with higher prevalence of metastatic cancer (33% vs. 20%; PR: 1.64, 95% confidence interval [CI]: 1.13-2.38), cancers exhibiting mismatch repair deficiency (79% vs. 56%; PR: 1.40, 95% CI: 1.13-1.72), and proximally located cancers (54% vs. 40%; PR: 1.34, 95% CI: 1.06-1.69). The one- and five -year adjusted hazard ratios (HRs) of death for PCCRC vs. dCRC among UC patients were 1.29 (95% CI: 0.77-2.18) and 1.24 [95% CI: 0.86-1.79), respectively.

CONCLUSION: The characteristics of UC-related PCCRC suggest tumor biology as an important factor in the progression to cancer. However, the prognosis of PCCRC appears similar to that of dCRC.

BACKGROUND & AIMS: Compared with drugs plus endoscopy, placement of transjugular portosystemic shunt within 72 hours of admission to the hospital (early or preventive transjugular intrahepatic portosystemic shunt [TIPS], also called preemptive TIPS) increases the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survive for 1 year. However, the benefit of preemptive TIPS is less clear for patients with a Child-Pugh score of B and active bleeding (CP-B+AB). We performed an individual data meta-analysis to assess the efficacy of preemptive TIPS in these patients and identify factors associated with reduced survival of patients receiving preemptive TIPS.
 
METHODS: We searched publication databases for randomized controlled trials and observational studies comparing the effects of preemptive TIPS versus endoscopy plus nonselective beta-blockers in the specific population of high-risk patients with cirrhosis and acute variceal bleeding (CP-B+AB or Child-Pugh C, below 14 points), through December 31, 2019. We performed a meta-analysis of data from 7 studies (3 randomized controlled trials and 4 observational studies), comprising 1327 patients (310 received preemptive TIPS and 1017 received drugs plus endoscopy). We built adjusted models to evaluate risk using propensity score for baseline covariates. Multivariate Cox regression models were used to assess the factors associated with survival time. The primary endpoint was effects of preemptive TIPS versus drugs plus endoscopy on 1-year survival in the overall population as well as CP-B+AB and Child-Pugh C patients.
 
RESULTS:

• Overall, preemptive TIPS significantly increased the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survived for 1 year, compared with drugs plus endoscopy (hazard ratio [HR] 0.443; 95% CI 0.323-0.607; P < .001).

 

• This effect was observed in Child sore A and B patients (HR 0.524; 95% CI 0.307-0.896; P = .018) and in patients with Child-Pugh C scores below 14 points (HR 0.374; 95% CI 0.253-0.553; P < .001).

 

• Preemptive TIPS significantly improved control of bleeding and ascites without increasing risk of hepatic encephalopathy in Child-Pugh A, B and patients, compared with drugs plus endoscopy.

 
Cox analysis of patients who received preemptive TIPS showed that patients could be classified into 3 categories for risk of death, based on age, serum level of creatinine, and Child-Pugh score. In each of these risk categories, preemptive TIPS increased the proportion of patients who survived for 1 year, compared with drugs plus endoscopy.
 
CONCLUSIONS: In a meta-analysis of data from 1327 patients with cirrhosis, acute variceal bleeding, and Child-Pugh score between 10 and 13 points or CP-B+AB, preemptive TIPS increased the proportion who survived for 1 year, in both subgroups separately, compared with drugs plus endoscopy. 

1. ESGE recommends that the initial assessment of patients presenting with acute lower gastrointestinal bleeding should include: a history of co-morbidities and medications that promote bleeding; hemodynamic parameters; physical examination (including digital rectal examination); and laboratory markers. A risk score can be used to aid, but should not replace, clinician judgment. 
Strong recommendation, low quality evidence. 

2. ESGE recommends that, in patients presenting with a self-limited bleed and no adverse clinical features, an Oakland score of <= 8 points can be used to guide the clinician decision to discharge the patient for outpatient investigation. 
Strong recommendation, moderate quality evidence. 

3. ESGE recommends, in hemodynamically stable patients with acute lower gastrointestinal bleeding and no history of cardiovascular disease, a restrictive red blood cell transfusion strategy, with a hemoglobin threshold of <= 7 g/dL prompting red blood cell transfusion. A post-transfusion target hemoglobin concentration of 7-9 g/dL is desirable.
Strong recommendation, low quality evidence. 

4. ESGE recommends, in hemodynamically stable patients with acute lower gastrointestinal bleeding and a history of acute or chronic cardiovascular disease, a more liberal red blood cell transfusion strategy, with a hemoglobin threshold of <= 8 g/dL prompting red blood cell transfusion. A post-transfusion target hemoglobin concentration of >= 10 g/dL is desirable. Strong recommendation, low quality evidence. 

5. ESGE recommends that, in patients with major acute lower gastrointestinal bleeding, colonoscopy should be performed sometime during their hospital stay because there is no high quality evidence that early colonoscopy influences patient outcomes.
Strong recommendation, low quality of evidence. 

6. ESGE recommends that patients with hemodynamic instability and suspected ongoing bleeding undergo computed tomography angiography before endoscopic or radiologic treatment to locate the site of bleeding.
Strong recommendation, low quality evidence. 

7. ESGE recommends withholding vitamin K antagonists in patients with major lower gastrointestinal bleeding and correcting their coagulopathy according to the severity of bleeding and their thrombotic risk. In patients with hemodynamic instability, we recommend administering intravenous vitamin K and four-factor prothrombin complex concentrate (PCC), or fresh frozen plasma if PCC is not available.
Strong recommendation, low quality evidence. 

8. ESGE recommends temporarily withholding direct oral anticoagulants at presentation in patients with major lower gastrointestinal bleeding.
Strong recommendation, low quality evidence. 

9. ESGE does not recommend withholding aspirin in patients taking low dose aspirin for secondary cardiovascular prevention. If withheld, low dose aspirin should be resumed, preferably within 5 days or even earlier if hemostasis is achieved or there is no further evidence of bleeding.
Strong recommendation, moderate quality evidence. 

10. ESGE does not recommend routinely discontinuing dual antiplatelet therapy (low dose aspirin and a P2Y12 receptor antagonist(clopidogrel, ticagrelor, prasugrel) before cardiology consultation. Continuation of the aspirin is recommended, whereas the P2Y12 receptor antagonist can be continued or temporarily interrupted according to the severity of bleeding and the ischemic risk. If interrupted, the P2Y12 receptor antagonist should be restarted within 5 days, if still indicated.
Strong recommendation, low quality evidence. 

BACKGROUND/AIMS: Prolonged repetitive strain caused by the continuous performance of complex endoscopic procedures enhances the risk of ergonomic injuries among health-care providers (HCPs), specifically endoscopists. This study aimed to assess the risk factors of ergonomic injuries among endoscopists and non-endoscopists.

METHODS: This cross-sectional study was conducted at the Gastroenterology Department of Liaquat National Hospital, Karachi, Pakistan. A total of 92 HCPs were enrolled, of whom 61 were involved in endoscopic procedures and 31 were non-endoscopists. Data were collected through a self-administered questionnaire during national gastroenterology conferences and analyzed using SPSS version 22 (IBM Corp. Chicago, IL, USA).

RESULTS: Of the total study population, 95.08% of endoscopists were observed to have ergonomic injuries, whereas only 54.83% of non-endoscopists had ergonomic injuries (p<0.00). The most common injury associated with musculoskeletal (MSK) pain sites was back (41%), leg (23%), and hand (19.7%) pain among endoscopists. Of 28 endoscopists performing >=20 procedures/week, 26 had MSK injury. However, 95.08% of endoscopists had developed MSK injury irrespective of working hours (>5 or <5 hr/wk).

CONCLUSION: Endoscopists are at high risk of developing ergonomic injuries, representing the negative potential of the endoscopy-associated workload. To overcome these issues, an appropriate strategic framework needs to be designed to avoid occupational compromises.

Efficacy of Therapy for Eosinophilic Esophagitis in Real-World Practice.
Clinical Gastroenterology & Hepatology. 18(13):2903-2911.e4, 2020 12.
Authors Laserna-Mendieta EJ; Casabona S; Savarino E; Perello A; Perez-Martinez I et. al.

Analysis of data from the EoE CONNECT database-of nearly 600 patients from 11 Spanish centres which was started in 2016
Topical steroids, proton pump inhibitors (PPIs), and dietary interventions are recommended first- and second-line therapies for eosinophilic esophagitis (EoE). We investigated differences in their effectiveness in a real-world, clinical practice cohort of patients with EoE.

METHODS: We collected data on the efficacy of different therapies for EoE (ability to induce clinical and histologic remission) from the multicenter EoE CONNECT database-a database of patients with a confirmed diagnosis of EoE in Europe that began in 2016. We obtained data from 589 patients, treated at 11 centers, on sex, age, time of diagnosis, starting date of any therapy, response to therapy, treatment end dates, alternative treatments, and findings from endoscopy. The baseline endoscopy was used for diagnosis of EoE; second endoscopy was performed to evaluate response to first-line therapies. After changes in treatment, generally because lack of efficacy, a last endoscopy was performed. The time elapsed between endoscopies depended on the criteria of attending physicians. Clinical remission was defined by a decrease of more than 50% in Dysphagia Symptom Score; improvement in symptoms by less than 50% from baseline was considered as clinical response. Histologic remission was defined as a peak eosinophil count below 5 eosinophils/hpf. A peak eosinophil count between 5 and 14 eosinophils/hpf was considered histologic response. We identified factors associated with therapy selection and effectiveness using chi2 and multinomial logistic regression analyses

  RESULTS: Summary of the findings:

• First-line treatment was PPI in 75%, topical steroids in 10% and elimination diets in 8%.
• Topical steroids induced histological remission in 68% of patients, elimination diets in 52% and PPIs in 50%.
• Second-line therapy was dietary interventions in 47% of patients, PPIs in for 29% and topical steroids in 18%).
• Patients with strictures were more likely to be given a topical steroids

 
Lack of fibrotic features at initial endoscopy was associated with selection of elimination diets over topical steroids as a second-line therapy. The recruiting center was significantly associated with therapy choice; second-line treatment with topical steroids or PPIs were the only variables associated with clinical and histologic remission.

  CONCLUSIONS: In an analysis of data from a large cohort of patients with EoE in Europe, we found topical steroids to be the most effective at inducing clinical and histologic remission, but PPIs to be the most frequently prescribed. Treatment approaches vary with institution and presence of fibrosis or strictures.
 
PPI was surprisingly effective and seems well worth trying before starting topical steroids

Effectiveness and Safety of High- vs Low-Dose Swallowed Topical Steroids for Maintenance Treatment of Eosinophilic Esophagitis: A Multicenter Observational Study.
Clinical Gastroenterology & Hepatology.  2020 Aug 13.
Authors Greuter T; Godat A; Ringel A; Almonte HS; Schupack D; Mendoza G; McCright-Gill T;, et.al. 
 
 BACKGROUND & AIMS: Data evaluating efficacy of different doses of swallowed topical corticosteroids (STC) in the long-term management of eosinophilic esophagitis (EoE) are lacking. We assessed long-term effectiveness and safety of different STC doses for adults with EoE after achievement of histological remission.

  METHODS: We performed a retrospective multicenter study at five EoE referral centers (US and Switzerland). We analyzed data on 82 patients with EoE in histological remission and ongoing STC treatment with therapeutic adherence of >=75% (58 males; mean age at diagnosis, 37.2+/-14.4 years). Patients were followed for a median of 2.2 years (interquartile range [IQR], 1.0-3.8 years). We collected data from 217 follow-up endoscopy visits. The primary endpoint was time to histological relapse.

  RESULTS: Histological relapse occurred in 67% of patients. Relapse rates were comparable in patients taking low dose (<=0.5 mg per day, n = 58) and high dose STC (>0.5 mg per day, n = 24) with 72 vs 54% (ns). However, histological relapse occurred significantly earlier with low dose STC (1.0 vs 1.8 years, P = .030). There was no difference regarding rates of and time to stricture formation for low vs high dose STC. Esophageal candidiasis was observed in 6% of patients (5% for low dose, 8% for high dose, ns). No dysplasia or mucosal atrophy was detected.

  CONCLUSION: Histological relapse frequently occurs in EoE despite ongoing STC treatment regardless of STC doses. However, relapse develops later in patients on high dose STC without an increase in side-effects. Doses higher than 0.5 mg/day may be considered for EoE maintenance treatment, but advantage over lower doses appears to be small. Copyright &#xa9; 2020 AGA Institute. Published by Elsevier Inc. All rights reserved.
 
Presumably this was patients who had attained remission with topical steroids?  Remember that about 1/3 of patients don’t respond.   Of course, the potential benefits of systemic glucocorticosteroids in EoE patients that are refractory to topical glucocorticosteroids are currently unknown.

 Endoscopic retrograde appendicitis therapy (ERAT) for management of acute appendicitis.
Surgical Endoscopy.  2021 May 13.
Authors Ding W; Du Z; Zhou X

 BACKGROUND: This study investigated the feasibility of endoscopic retrograde appendicitis therapy (ERAT) for the treatment of acute appendicitis.

  METHODS: There were 210 patients included who were admitted to our hospital from January 2017 to October 2019 with a diagnosis of acute appendicitis. According to the method of treatment, patients were stratified into the ERAT group, laparoscopic appendectomy (LA) group, or open appendectomy (OA) group for comparison of perioperative information extracted from the medical records of the patients.

  RESULTS: The operations were successfully completed in all patients. The length of operation in the endoscopy group (median: 48 min, range: 34-78 min) was significantly shorter compared to the Laparoscopic group (median: 67 min, range: 47-90 min) or open surgery group (median: 85 min, range: 58-120 min).
Postoperatively, the length of stay, the amount of time spent bedridden following surgery, surgery-related complications, and in-patient expenses were all significantly less in the Endoscopic than in pts managed surgically (all p < 0.05).
Moreover, the recurrence rate of appendicitis after Endoscopic treatment was 1: 30 (2.86%) during the first 6 months of postoperative follow-up.

13 patients who underwent the Endoscopic treatment developed an appendicular abscess.  These were all successfully treated colonoscopically incising the most protruding or fluctuating place around the appendix opening without procedure-related complications during the follow-up period.

  CONCLUSION: Endoscopic treatment is a safe and effective endoscopic treatment method for acute appendicitis and abscesses of the appendix. The advantages include reduced trauma, faster recovery times, and lower costs in comparison with either surgical procedures. ERAT with internal incision and drainage can be safely performed with immediate effect, especially in patients with acute uncomplicated appendicitis accompanied by either fecal stones or stenosis of the appendix cavity, or an abscess within the appendix cavity.

 To remind you, the idea that we may be able to treat appendicitis goes back to 2012

• Liu BR, Song JT, Han FY, et al. Endoscopic retrograde appendicitis therapy: a pilot minimally invasive technique (with videos). Gastrointest Endosc 2012;76:862-6.
• It was called Endoscopic retrograde appendicitis therapy (ERAT) by the Chinese
• ERAT includes the following steps:
  • colonoscopy with a cap  (to help observation of the appendiceal orifice
  • insertion of a catheter over a guidewire into the appendix lumen under fluoroscopy control and injection contrast to outline the anatomy
  • Washing with saline solution through the catheter
  • Removal of any faecoliths with a basket or retrieval balloon
  • If there is a stricture, a straight biliary plastic stent is placed

ERCP within 6 or 12 h for acute cholangitis: a propensity score-matched analysis.
Surgical Endoscopy.  2021 May 11.
Authors Becq A; Chandnani M; Bartley A; Nuzzo A; Bilal M; Bharadwaj S; Cohen J; et.al. 

 BACKGROUND: The optimal timing of ERCP for patients with acute cholangitis remains controversial. The aim of our study was to determine if ERCP performed within 6 or 12 h of presentation was associated with improved clinical outcomes.

  METHODS: Medical records for all patients with acute cholangitis who underwent ERCP at our institution between 2009 and 2018 were reviewed. Outcomes were compared between those who underwent ERCP within or after 12 h using propensity score framework. Our primary outcome was length of hospitalization. Secondary outcomes included in-hospital mortality, adverse events, ERCP failure, length of ICU stay, organ failure, recurrent cholangitis, and 30-day readmission. In secondary analysis, outcomes for ERCP done within or after 6 h were also compared.

  RESULTS: During study period, 487 patients with cholangitis were identified, of whom 147 (30% of all patients) had ERCP within 12 h of presentation. Using propensity score matching, we selected 145 pairs of patients with similar characteristics.

• Length of hospitalization was similar between ERCP within or after 12 h (135.9 vs 122.1 h, p 0.094).
• No difference was noted in complications, length of ICU stay and mortality
  
  

CONCLUSIONS: ERCP performed within 6 h or 12 h of presentation was not associated with superior clinical outcomes, however, may result in reduced re-hospitalization.

Of course, most tertiary referral centres are unable to offer emergency ERCP in the middle of the night.  It would have been interesting to learn about the outcomes in comparing ERCP within 12 hours vs within 24 hours.  My own take-home message is that any patient with evidence of septic shock need ERCP within 24 hours and perhaps even within 12 hours
(which of course means the next day).

As you know, acute cholangitis is a medical emergency linked with a 2-5% mortality rate and ERCP can be life-saving

• Several meta-analyses have shown a 20% mortality reduction if ERCP is offered within 24 hours of admission
• The 2019 ESGE guideline recommend ERCP within 48–72 hours for moderate cholangitis and within <12 hours for severe acute cholangitis. 
• There are problems with this as it relies on around the clock immediate CT, ready availability of nurses, and imaging staff, anaesthetists, intensivists and an ERCP’ist
• It can also be a little difficult to distinguish moderate from the 1/3 patients who actually have severe cholangitis.  The mortality rate of patients with septic shock is close to 100% unless biliary drainage is quickly achieved.
• The ‘Tokyo definition of ‘moderate cholangitis’ includes WCC >12, fever >39, age >75 yrs, bili >85 umol/l or, hypoalbuminaemia
  • Severe disturbance of cardiovascular, neurological, respiratory, renal, hepatic or haematological system. 

Increased Risk of Advanced Colonic Adenomas and Timing of Surveillance Colonoscopy Following Solid Organ Transplantation.
Digestive Diseases & Sciences.  2021 May 10.
Authors Ashkar MH; Chen J; Shy C; Crippin JS; Chen CH; Sayuk GS; Davidson NO

 BACKGROUND: Detection and removal of colonic adenomatous polyps decreases colorectal cancer (CRC) development, particularly with more or larger polyps or polyps with advanced villous/dysplastic histology. Immunosuppression following solid organ transplantation may accelerate adenomas development and progression compared to average-risk population but the benefit of earlier colonoscopic surveillance is unclear.

  AIMS: Study the impact of maintenance immunosuppression post-transplantation on developmental timing, multiplicity and pathological features of adenomas, by measuring incidence of advanced adenomas (villous histology, size >= 10 mm, >= 3 polyps, presence of dysplasia) post-transplantation and the incidence of newly diagnosed CRC compared to average-risk age-matched population.

  METHODS: Single-center retrospective cohort study of transplantation recipients.

  RESULTS: 295 transplantation recipients were included and were compared with 291 age-matched average-risk controls. The mean interval between screening and surveillance colonoscopies between transplantation and control groups was 6.3 years vs 5.9 years (p = 0.13). Post-transplantation maintenance immunosuppression mean duration averaged 59.9 months at surveillance colonoscopy. On surveillance, transplantation recipients had more large adenomas (10 mm or larger) compared to matched controls (9.2% vs. 3.8%, p = 0.034; adjusted OR 2.38; 95% CI 1.07-5.30).

  CONCLUSION: transplantation recipients appear at higher risk for developing advanced adenomas, suggesting that earlier surveillance should be considered.
 
Does immunosuppression also suppress our bodies ability to keep rouge DNA in check?  Or does this study simply show that if you are on a transplant list, attending for screening colonoscopy is a low priority?

Predicting the need for step-up therapy after EUS-guided drainage of pancreatic fluid collections with lumen-apposing metal stents.
Clinical Gastroenterology & Hepatology.  2021 May 06.
Authors Chandrasekhara V; Elhanafi S; Storm AC; Takahashi N, et.al. 

 BACKGROUND & AIMS: A significant proportion of individuals with pancreatic fluid collections (PFCs) require step-up therapy after endoscopic drainage with lumen-apposing metal stents (LAMS). The aim of this study is to identify factors associated with PFCs that require step-up therapy.

  METHODS: A retrospective cohort study of patients undergoing EUS-guided drainage of PFCs with LAMS from 4/2014 to 10/2019 at a single center was performed.

• Step-up therapy included direct endoscopic necrosectomy (DEN),
• additional drainage site (endoscopic or percutaneous), or
• surgical intervention after the initial drainage procedure.

Multivariable logistic regression was performed using a backward stepwise approach with a p <= 0.2 threshold for variable retention to identify factors predictive for the need for step-up therapy.

  RESULTS: 136 patients who had their collections drained with a stent,  were included in the final study cohort, of whom 69 (50.7%) required step-up therapy. Independent predictors of step-up therapy included:

• collection size measuring >10 cm (OR 8.91, 95% CI 3.36-23.61),
• paracolic extension of the PFC (OR 4.04, 95% CI 1.60-10.23), and
• >30% solid necrosis (OR 4.24, 95% CI 1.48-12.16).

In a sensitivity analysis of 51/81 patients (63.0%) required step-up therapy, mainly ‘Endoscopic Necrosectomy. Similarly, factors predictive of the need for step-up therapy for WON included: collection size measuring >10 cm (OR 6.94, 95% CI 1.76-27.45), paracolic extension of the PFC (OR 3.79, 95% CI 1.18-12.14), and >30% solid necrosis (OR 7.10, 95% CI 1.16-43.48)

CONCLUSIONS: Half of all patients with PFCs drained with LAMS required step-up therapy, most commonly DEN. Individuals with PFCs >10 cm in size, paracolic extension, or >30% solid necrosis are more likely to require step-up therapy and should be considered for early endoscopic re-intervention. .

Endoscopic Necrosectomy With and Without Hydrogen Peroxide for Walled-off Pancreatic Necrosis: A Multicenter Comparative Study.
American Journal of Gastroenterology. 116(4):700-709, 2021 Apr.
Authors Messallam AA; Adler DG; Shah RJ; Nieto JM, et.al. 

 INTRODUCTION: Endoscopic necrosectomy has emerged as the preferred treatment modality for walled-off pancreatic necrosis. This study was designed to evaluate the safety and efficacy of direct endoscopic necrosectomy with and without hydrogen peroxide (H2O2) lavage.

  METHODS: Retrospective chart reviews were performed for all patients undergoing endoscopic transmural management of walled-off pancreatic necrosis at 9 major medical centers from November 2011 to August 2018. Clinical success was defined as the resolution of the collection by imaging within 6 months, without requiring non-endoscopic procedures or surgery.

  RESULTS: Of 293 patients, 204 patients met the inclusion criteria. Technical and clinical success rates were 100% (204/204) and 81% (166/189), respectively. For patients, 122 (59.8%) patients had at least one hydrogen peroxide necrosectomy and 82 (40.2%) patients had standard endoscopic necrosectomy.

• Clinical success was higher in the hydrogen peroxide group: 106/113 (95%) vs 60/76 (80%), P = 0.002.
• In addition, resolution was quicker with hydrogen peroxide (odds ratio 2.27, P < 0.001).
• During a mean follow-up of 274 days, there were 27 complications (5% vs 8%), P = 0.30..
  • no difference in post-procedure bleeding (7 vs 9, P = 0.25), perforation (2 vs 3, P = 0.66), infection (1 vs 2, P = 0.58)

  DISCUSSION: Hydrogen peroxide assisted endoscopic necrosectomy had a higher clinical success rate and a shorter time to resolution with equivalent complication rates relative to standard necrosectomy.

Timing of bleeding and thromboembolism associated with endoscopic submucosal dissection for gastric cancer in Japan.
Journal of Gastroenterology & Hepatology.  2021 May 07.
Authors Shiroma S; Hatta W; Tsuji Y; Yoshio T; Yabuuchi Y, et.al. 

 OBJECTIVE: This study aimed to reveal the timing of bleeding and thromboembolism associated with endoscopic submucosal dissection (ESD) for early gastric cancer (EGC).

  METHODS: We retrospectively reviewed 10,320 patients who underwent ESD for EGC during November 2013-October 2016. We evaluated overall bleeding rates and their inter-group differences. Factors associated with early/late (cut-off 5 days) bleeding and thromboembolism frequency and its association with the intake of antithrombotic (AT) agents were investigated.

  RESULTS: Overall, the post-ESD bleeding rate was 4.7% (489/10,320);

• • the median time to post-ESD bleeding was 4 days.
  • The post-ESD bleeding rates were 3% in pts not taking any antithrombotics, 9% in pts taking antiplatelets agents, 15% in pts taking anticoagulants, and 30% in those taking both antiplatelet and anticoagulants
  • Other risk factors for bleeding included chronic kidney disease with hemodialysis (OR, 2.93), lesion size >30 mm (OR, 1.86), multiple EGC’s resected (OR, 1.54), and having a lesion in the antrum (OR, 1.40) and cirrhosis (OR, 2.43), ischemic heart disease (OR, 1.77), and male sex (OR, 1.65).
  • There were three (0.03%) thromboembolic events (cerebral infarction=2, transient ischemic attack=1).
    
    

CONCLUSION: We revealed the timing of bleeding and risk factors for early/late bleeding and showed the thromboembolism frequency associated with ESD for EGC. Copyright This article is protected by copyright. All rights reserved.

Of course we already know that the risk of bleeding after gastric EMR and gastric ESD is the same.  I will be using this data when I consent patients for a gastric resection of any lesion.

Benefits of linked color imaging for recognition of early differentiated-type gastric cancer: in comparison with indigo carmine contrast method and blue laser imaging.
Surgical Endoscopy. 35(6):2750-2758, 2021 Jun.
Authors Yasuda T; Yagi N; Omatsu T; Hayashi S; Nakahata Y, et/al. 

 BACKGROUND AND AIM: Linked colour imaging is proprietary Fujifilm technology which enhances slight differences in mucosal color. However, whether LCI is more useful than other kinds of image-enhanced endoscopy (IEE) in recognizing early gastric cancer remains unclear. This study aimed to evaluate LCI efficacy compared with the indigo carmine contrast method (IC), and blue laser imaging-bright (BLI-brt) in early differentiated-type gastric cancer recognition.

  METHODS: We retrospectively analyzed early differentiated-type gastric cancer, which were examined by all four imaging techniques (white light imaging, IC, LCI, BLI-brt) at Asahi University Hospital from June 2014 to November 2018. Both subjective evaluation (using ranking score: RS) and objective evaluation (using color difference score: CDS) were adopted to quantify early differentiated-type gastric cancer recognition.

  RESULTS: During this period, 87 EGC lesions were enrolled in this study. Both RS and CDS of LCI were significantly higher (p < 0.01) than those of IC and BLI-brt.  Both RS and CDS of BLI-brt had no significant difference compared with those of IC. Subgroup analysis indicated that Linked colour imaging may be better than Indigo carmine dye particularly in finding flat or depressed lesions.

CONCLUSIONS: LCI appears to be more beneficial for the recognition of early differentiated-type gastric cancer in endoscopic screenings than IC and BLI-brt from the middle to distant view.

Narrowband imaging with near-focus magnification for discriminating the gastric tumor margin before endoscopic resection: A prospective randomized multicenter trial.
Journal of Gastroenterology & Hepatology. 35(11):1930-1937, 2020 Nov.
Authors Kim JW; Jung Y; Jang JY; Kim GH; Bang BW; Park JC; Choi HS, et.al. 
Prospective randomized controlled trial was conducted at seven teaching hospitals in South Korea

 BACKGROUND AND AIM: This study investigated the usefulness of near-focus narrowband imaging (NF-NBI) for determining gastric tumor margins compared with indigo carmine chromoendoscopy (ICC) before endoscopic submucosal dissection (ESD).

  METHODS: This prospective randomized controlled trial was conducted at seven teaching hospitals in Korea. Patients with gastric adenoma or differentiated adenocarcinoma undergoing ESD were enrolled and randomly assigned to the NF-NBI or ICC group. A marking dot was placed on the most proximal margin of the tumor before ESD. The primary endpoint was delineation accuracy, which was defined as presence of marking dots within 1 mm of the tumor margin under microscopic observation.

  RESULTS: A total of 200 patients had ‘Near Focus NBI’ and 195 patients had indigo carmine dye to delineate the margin of the EGC’s. The delineation Accuracy rate was 85% in the ‘Near Focus NBI’ group and 80.0% in the ‘indigo carmine dye spray’ group (P = 0.44). However, the distance from the marking dot to the margin of the tumor was significantly shorter in the ‘Near Focus NBI’ group than in the ‘indigo carmine dye spray’  group (0.8 +/- 0.8 vs 1.2 +/- 1.3 mm, P < 0.01). Even after adjustment of other clinicopathological factors that are associated with difficulty of tumor delineation, ‘Near Focus NBI’ did not show significant association with accurate delineation (odds ratio of 0.86, P = 0.60).

  CONCLUSIONS: The authors concluded that Near Focus and NBI was not significantly better than Indigo Carmine spray to accurately delineating gastric tumors

Risk factors affecting failure of colonoscopic detorsion for sigmoid colon volvulus: a single center experience.
International Journal of Colorectal Disease. 36(6):1221-1229, 2021 Jun.
Authors Surek A; Akarsu C; Gemici E; Ferahman S; Dural AC; Bozkurt MA, et.al. 

 PURPOSE: Colonoscopic detorsion (CD) is the first treatment option for uncomplicated sigmoid volvulus (SV). We aim to examine the factors affecting the failure of CD.

  METHODS: The files of patients, treated after diagnosis of SV between January 2015 and September 2020, were retrospectively reviewed. Patients' demographic data, comorbidities, endoscopy reports, and surgical and other treatments were recorded. Patients were divided into two groups, as the successful CD group and unsuccessful CD group. The data were compared between the groups, and multivariate analysis of statistically significant variables was performed.

  RESULTS: There were 21 (30%) patients had a failed sigmoidoscopic detorsion and 52 patients underwent a successful procedure. [This is greater than the 95% success rate reported in previous studies but of course, the chance of success must be very operator dependent].  The unsuccessful CD rate was found to be 28.76%; this is likely a function of.  Risk factors for failure included;

• neuropsychiatric disease
• sigmoid diverticular disease
• previous abdominal surgery (an earlier Japanese study from 2017 had indicated that this group was more likely to have a successful endoscopic detorsion)
• abdominal tenderness
• onset of symptoms for more than 48 h
• mean intra-abdominal pressure >15 mmHg,
• larger mean diameter of the cecum, (>10cm)
• higher CRP

 
values as statistically significant. In the multivariate analysis, previous abdominal surgery and cecum diameter over 10 cm were seen as predictive factors for failure of CD (p=0.049, OR=0.103, and p = 0.028, OR=10.540, respectively).

  CONCLUSIONS: CD failure rate was significantly associated with previous abdominal surgery and a cecum diameter over 10 cm. We found that patients with these factors will tend to need more emergency surgery.
 
Not for the first time in medicine do we find that the patients in the greatest need of a successful outcome of a medical intervention, is precisely the group who is the least likely to benefit ! 

Transition to quantitative faecal immunochemical testing from guaiac faecal occult blood testing in a fully rolled-out population-based national bowel screening programme.
Gut. 70(1):106-113, 2021 Jan.
Authors Clark G; Strachan JA; Carey FA; Godfrey T; Irvine A; McPherson A; Brand J; Anderson AS, et.al. 

 OBJECTIVE: Faecal immunochemical tests (FIT) are replacing guaiac faecal occult blood tests (FOBT) in colorectal cancer (CRC) screening. Data from the first year of FIT screening were compared with those from FOBT screening and assumptions based on a pilot evaluation of FIT.

  DESIGN: Data on uptake, positivity, positive predictive value (PPV) for CRC and higher-risk adenoma from participants in the first year of the FIT-based Scottish Bowel Screening Programme (n=919 665), with a threshold of 80 microg Hb/g faeces, were compared with those from the penultimate year of the FOBT-based programme (n=862 165) and those from the FIT evaluation (n=66 225).

  RESULTS: Overall

• FIT uptake was 63.9% compared with 56.4% for FOB
• Test positivity was 3.1% for FIT compared with and 2.2% for FOB
• The PPV for CRC was 5.2% with FIT and 6.4% with FOBT (a fall in predictive value).
• The PPV for high risk adenoma was 24.3% for FIT vs 19.3% for FOB

  CONCLUSION: Transition to FIT from FOBT produced higher uptake and positivity with lower PPV for CRC and higher PPV for adenoma. The FIT pilot evaluation underestimated uptake and positivity. Introducing FIT at the same threshold as the evaluation caused a 67.2% increase in colonoscopy demand instead of a predicted 10%
 
The whole of the UK has moved from guaiac based FOB testing to faecal immunochemical FIT test.  This study only pertains to the Scottish experience but I see no reason why their findings would be different to the UK experience as a whole.

I remember being told that the best thing about FIT testing is that you can change the sensitivity of the test so that my colonoscopy service doesn’t become overwhelmed.   Well that was never going to happen was it?   That dial is welded into place and nothing short of a declaration in the house of Parliament would move it

Performance evaluation of stool DNA methylation tests in colorectal cancer screening: a systematic review and meta-analysis.
Colorectal Disease. 23(5):1030-1042, 2021 05.
Authors Gachabayov M; Lebovics E; Rojas A; Felsenreich DM; Latifi R; Bergamaschi R

 AIM: There is not sufficient evidence about whether stool DNA methylation tests allow prioritizing patients to colonoscopy. Due to the COVID-19 pandemic, there will be a wait-list for rescheduling colonoscopies once the mitigation is lifted. The aim of this meta-analysis was to evaluate the accuracy of stool DNA methylation tests in detecting colorectal cancer.

  METHODS: 46 studies including a total of  16,000 patients were included in this meta-analysis. The PubMed, Cochrane Library and MEDLINE via Ovid were searched. Studies reporting the accuracy (Sackett phase 2 or 3) of stool DNA methylation tests to detect sporadic colorectal cancer were included. The DerSimonian-Laird method with random-effects model was utilized for meta-analysis.

  RESULTS: 46 studies totaling 16 149 patients were included in the meta-analysis. The pooled sensitivity and specificity of all single genes and combinations was 62.7% (57.7%, 67.4%) and 91% (89.5%, 92.2%), respectively. Combinations of genes provided higher sensitivity compared to single genes (80.8% [75.1%, 85.4%] vs. 57.8% [52.3%, 63.1%]) with no significant decrease in specificity (87.8% [84.1%, 90.7%] vs. 92.1% [90.4%, 93.5%]).

• The most accurate single gene was ‘SDC2’ with a sensitivity of 83.1% (72.6%, 90.2%) and a specificity of 91.2% (88.6%, 93.2%).  This means that 15% of patients with a cancer had a false negative test and nearly 10% of patients tested had a false positive test. 

  CONCLUSIONS: Stool DNA methylation tests have high specificity (92%) with relatively lower sensitivity (81%). Combining genes increases sensitivity compared to single gene tests. The single most accurate gene is SDC2, which should be considered for further research.
 
Clearly testing stool for DNA methylation is almost but not quite ready for prime time ! 

​Association Between Endoscopist Annual Procedure Volume and Colonoscopy Quality: Systematic Review and Meta-analysis.
Clinical Gastroenterology & Hepatology. 18(10):2192-2208.e12, 2020 09.
Authors Forbes N; Boyne DJ; Mazurek MS; Hilsden RJ; Sutherland RL, et.al. 
A systematic review of 27 studies of 11,000 000 colonoscopies looking at flight hours vs quality

 BACKGROUND & AIMS: In addition to monitoring adverse events (AEs) and post-colonoscopy colorectal cancers (PCCRC), indicators for assessing colonoscopy quality include adenoma detection rate (ADR) and cecal intubation rate (CIR). It is unclear whether there is an association between annual colonoscopy volume and ADR, CIR, AEs, or PCCRC.

  METHODS: We searched publication databases through March 2019 for studies assessing the relationship between annual colonoscopy volume and outcomes, including ADR, CIR, AEs, or PCCRC. Pooled odds ratios (ORs) were calculated using DerSimonian and Laird random effects models. Sensitivity analyses were performed to assess for potential methodological or clinical factors associated with outcomes.

  RESULTS: We performed a systematic review of 9235 initial citations, generating 27 retained studies comprising 11,276,244 colonoscopies.

• No link between procedural volume and ADR (OR, 1.00; 95% CI, 0.98-1.02 per additional 100 annual procedures).
• No link between procedural volume and PCCRC
• Caecal intubation rate improved with each additional 100 annual procedures (OR, 1.17; 95% CI, 1.08-1.28).

There was a non-significant trend toward decreased overall AEs per additional 100 annual procedures (OR, 0.95; 95% CI, 0.90-1.00). There was considerable heterogeneity among most analyses.

  CONCLUSIONS: In a systematic review and meta-analysis, we found higher annual colonoscopy volumes to correlate with higher CIR, but not with ADR or PCCRC. Trends toward fewer AEs were associated with higher annual colonoscopy volumes. There are few data available from endoscopists who perform fewer than 100 annual colonoscopies. Studies are needed on extremes in performance volumes to more clearly elucidate associations between colonoscopy volumes and outcomes.
 
Of course, hardly any studies included colonoscopists who did fewer than 100 procedures a year.  It looks like endoscopists who only do a small number of colonoscopies each year don’t readily volunteer their data.  Is there a threshold effect in that if you do a certain number of procedures each year, your ‘performance’ levels off and you don’t find any more adenomas ?   

Evaluation of Acute Mountain Sickness by Unsedated Transnasal Esophagogastroduodenoscopy at High Altitude.
Clinical Gastroenterology & Hepatology. 18(10):2218-2225.e2, 2020 09.
Authors Fruehauf H; Vavricka SR; Lutz TA; Gassmann M; Wojtal KA; Erb A, et.al. 

A prospective study, 25 Swiss mountaineers

 BACKGROUND & AIMS: It is not clear how rapid ascent to a high altitude causes the gastrointestinal symptoms of acute mountain sickness (AMS). We assessed the incidence of endoscopic lesions in the upper gastrointestinal tract in healthy mountaineers after a rapid ascent to high altitude, their association with symptoms, and their pathogenic mechanisms.

  METHODS: In a prospective study, 25 mountaineers (10 women; mean age, 45 underwent unsedated, transnasal esophagogastroduodenoscopy at ground level and then after 4 days in at a high altitude laboratory in the Alps (at 4559 meters). Symptoms were assessed using validated instruments for AMS (the acute mountain sickness score and the Lake Louise scoring system) and visual analogue scales (scale, 0-100). Levels of messenger RNAs (mRNAs) in duodenal biopsy specimens were measured by quantitative polymerase chain reaction.

  RESULTS: The follow-up endoscopy at high altitude was performed in 19 of 25 patients on day 2 and in 23 of 25 patients on day 4.

• The frequency of endoscopic lesions increased from 12% at baseline to 26% on day 2 and to 60% on day 4 (P < .001).
• ulcer disease increased from 0 at baseline to 10% on day 2 and to 22% on day 4 (P = .014)
• Mucosal lesions were associated with lower hunger scores (37.3 vs 67.4 in patients without lesions; P = .012).
• Subjects with peptic lesions had higher levels of HIF2A mRNA, (a hypoxia-induced transcription factor), and ICAM1 mRNA (an adhesion molecule) which may be the mediators of the mucosal damage.
  
  

  CONCLUSIONS: In a prospective study of 25 mountaineers, fast ascent to a high altitude resulted in rapid onset of clinically meaningful mucosal lesions and ulcer disease. Duodenal biopsy specimens from these subjects had increased levels of HIF2A mRNA and ICAM1 mRNA, which might contribute to the formation of hypoxia-induced peptic lesions. Further studies are needed of the mechanisms of this process. Copyright &#xa9; 2020 AGA Institute. Published by Elsevier Inc. All rights reserved.
 
I’m looking forward to a study of colonoscopy at the top of Mount Everest.  

Yield of Lynch Syndrome Surveillance for Patients With Pathogenic Variants in DNA Mismatch Repair Genes.
Clinical Gastroenterology & Hepatology. 18(5):1112-1120.e1, 2020 05.
Authors Goverde A; Eikenboom EL; Viskil EL; Bruno MJ et.al. 

A Retrospective analysis of surveillance data from a single centre in the Netherlands (Rotterdam)

 BACKGROUND & AIMS: Patients with Lynch syndrome are offered the same colorectal cancer (CRC) surveillance programs (colonoscopy every 2 years), regardless of the pathogenic DNA mismatch repair gene variant the patient carries. We aimed to assess the yield of surveillance for patients with these variants in MLH1, MSH2, MSH6, and PMS2.

  METHODS: We analyzed data on colonoscopy surveillance, including histopathology analysis, from all patients diagnosed with Lynch syndrome (n = 264 with Lynch Syndrome) at a single center. We compared the development of (advanced) adenomas and CRC among patients with pathogenic variants in the DNA mismatch repair genes MLH1 (n = 55), MSH2 (n = 44), MSH6 (n = 143), or PMS2 (n = 22) over 1836 years of follow-up (median follow-up of 6 years per patient).

  RESULTS: At first colonoscopy, CRC was found in 8 patients. During 916 surveillance colonoscopies, CRC was found in 9 patients and 6 patients died during follow up (5 from some cancer).. No CRC was found in patients with variants in MSH6 or PMS2 over the entire follow-up period. There were no significant differences in the number of colonoscopies with adenomas or advanced adenomas among the groups. The median time of adenoma development was 3 years (IQR, 2-6 years). There were no significant differences in time to development of adenoma.

• Patients with MSH6 mutations had a significant longer time to development of advanced neoplasia (advanced adenoma or CRC) than patients in the other groups.

  CONCLUSIONS: No CRC was found during follow-up of patients with Lynch syndrome carrying pathogenic variants in MSH6; advanced neoplasia developed over shorter follow-up time periods in patients with pathogenic variants in MLH1 or MSH2. The colonoscopy interval for patients with pathogenic variants in MSH6 might be increased to 3 years from the regular 2-year interval.
 
Mutations in the MSH6 mismatch repair is different!

Associations Between Mutations in MSH6 and PMS2 and Risk of Surveillance-detected Colorectal Cancer.
Clinical Gastroenterology & Hepatology. 18(12):2768-2774, 2020 11.
Authors Lamba M; Wakeman C; Ebel R; Hamilton S, et.al. 

Prospective study of 381 persons with Lynch syndrome in New Zealand

 BACKGROUND & AIMS: Lynch syndrome is the most common inherited cause of colorectal cancer (CRC). Contemporary and mutation-specific estimates of CRC-risk in patients undergoing colonoscopy would optimize surveillance strategies. We performed a prospective national cohort study, using data from New Zealand, to assess overall and mutation-specific risk of CRC in patients with Lynch syndrome undergoing surveillance.

  METHODS: We performed a prospective study of 381 persons with Lynch syndrome in New Zealand (98 with Lynch-syndrome associated variants in MLH1, 159 in MSH2, 103 in MSH6, and 21 in PMS2). Participants were offered annual colonoscopy starting at age 25 y, and those who underwent 2 or more colonoscopies before December 31, 2017 were included in the final analysis. Patients with previous colonic resection, history of CRC or diagnosis of CRC at index colonoscopy were excluded.

  RESULTS: Study participants underwent 2061 colonoscopies during a median of 4.4 year follow up 2296 person-y; the median observation-period was 4.43 y and mean-age at enrollment was 43 y.

• 18 patients (of 381 = 5%) developed CRC (8 with variants in MLH1, 8 in MSH2, and 2 in MSH6) after a median follow-up period of 6.5 y (range 1-16 y).
• 83% had a surveillance colonoscopy in preceding 24 months before diagnosis of CRC;
• 94% were diagnosed with early CRC and nobody died from bowel cancer.
• Cumulative risks for CRC in the variants were
  • MLH1 – 18% (8 cancers)
  • MSH2 – 18%  (8 cancers)
  • MSH6 – 8% (2 cancers)

 
Age-adjusted CRC-risk in patients with variants in MSH6 was lower than in MLH1 (hazard ratio, 0.2; 95% CI, 0.04-0.94; P = .02). Of patients with CRC, 33% had an adenomatous polyp resected from same segment in which a colorectal tumor later developed.

  CONCLUSIONS: The risk of CRC in patients with Lynch syndrome-associated mutations in MSH6 or PMS2 was significantly lower than in patients with mutations in MLH1. Incomplete adenomatous polyp resection might be responsible for one third of surveillance-detected CRCs.
 
Should we relax a little on surveillance intensity in patients with Lynch syndrome and the MSH6 variant?   Alternatively, as the risk of cancer was close to 20%, should patients with the MLH1 or the MSH2 mutations be offered total colectomy and only patients with MSH6 mutations be offered surgery?   The again nobody died from their bowel cancer.  And patients with Lynch syndrome have increased risk of small bowel cancer, pancreatic cancer, renal cancer, biliary tract cancer, brain cancer, prostate cancer and breast cancer !   We can’t remove or surveil most of these areas 

The optimal age to stop endoscopic surveillance of Barrett's esophagus patients based on sex and comorbidity: a comparative cost-effectiveness analysis.
Gastroenterology.  2021 May 08.
Authors Omidvari AH; Hazelton WD; Lauren BN, et.al. 

 BACKGROUND & AIMS: Current guidelines recommend surveillance for non-dysplastic Barrett's esophagus (NDBE) patients but do not include a recommended age for discontinuing surveillance. This study aimed to determine the optimal age for last surveillance of NDBE patients stratified by sex and level of comorbidity.

  METHODS: We used 3 independently developed models to simulate patients with stable Barrett’s, varying in age, sex, and comorbidity level (no, mild, moderate, severe). All patients had received regular surveillance until their current age. We calculated incremental costs and quality-adjusted life-years (QALYs) gained from one additional endoscopic surveillance at the current age versus not performing surveillance at that age. We determined the optimal age to end surveillance as the age at which incremental cost-effectiveness ratio (ICER) of one more surveillance was just below the willingness-to-pay threshold of $100,000/QALY.

  RESULTS: The benefit of having one more surveillance endoscopy strongly depended on age, sex and comorbidity. Carrying out 1000 Barrett’s surveillance gastroscopies in 80 yr old men with previously stable Barrett’s but with a severe comorbidity, provided 4 more quality-adjusted life-years (QALYs) at a cost of $1,2 million, while for women with severe comorbidity the benefit at that age was 7 QALYs at a cost of $1.3 million.

The authors concluded that the best time to stop was:

• Man with no comorbidity – 81 yrs (75 yrs in women)
• Man with mild comorbidity – 80 yrs (73 yrs in women)
• Man with moderate comorbidities – 77 yrs (73 yrs in women)
• Man with severe comorbidity – 73 yrs (69 yrs in women)

 
 CONCLUSIONS: Our comparative modelling analysis illustrates the importance of considering comorbidity status and sex when deciding upon the age to discontinue surveillance in patients with NDBE.
 
My generation has completely failed to pay any attention the cost, resource implications and climate impact of surveillance.  We subject our patients to uncomfortable surveillance from which they are very unlikely to benefit whilst squandering money and resources which could be used to provide these patients with health care which provides better value for the elderly.  Hip replacements, cataract surgery or perhaps better community care or whatever.  Surely, it’s not unreasonable to conclude that there comes a time in a patients life when surveillance is no longer appropriate and spending the money on other types of care is more appropriate? 

Once you had registered you were met by large entrance hall where you could click on:
1)      World of Science
2)      Industry exhibition
3)      My UEG Community
4)      TV study
5)      Missed a Session – repository of past sessions
6)      Industry Symposia
7)      Press
8)      Help desk
9)      Link to the app
 
World of Science gave you access to 6 ‘Halls’
·       All presentations had been pre-recorded but they felt ‘live’ as the session was introduced and managed by chairmen just like a normal meeting.
·       During and after the presentations there was an opportunity to ask questions which were first vetted and then uploaded for all to see
·       There was a total of 626 presentations, delivered during 177 sessions by 502 speakers as well as >1400 E-posters.

·       The IT side held up very well and all presentations streamed with good sound.  Sometimes it could be a little difficult to see the slides, even on a larger screen.  Of course, all the chairmen were actually sitting at home and occasionally their own WiFi signal dropped making the feed jerky.  However, this was far less of a problem than when taking part in a MS Teams meeting at work
 
Screening 1)      Early gastric cancer –
2)      Marco Dinis-Ribeiro from Porto reminded us about the MAPS guidelines.  He quoted several papers to claim that we can diagnose gastric intestinal metaplasia endoscopically without need for histological confirmation;
§  Pimentel-Nunes P. Endoscopy 2016;48(8);723-30,   
§  Ang TL. J Gastroenterol Hepatol 2015; 27: 1473–1478,   
§  Lage J. Scand J Gastroenterol 2016; 51: 501–506,    Marcos P. Gut 2019;69;1762-8
3)      Basically, it’s things like NBI or BLI which increases the endoscopic detection rates from quote poor 50% to close to 90%.  Gastric atrophy on the other hand remains difficult to diagnose both endoscopically and histologically
4)      Whether this holds true on busy, normal jobbing endoscopy lists, outside of specialist centres has not yet been proven.
§  reminding us of the MAPS II guidelines of 2019 by Marco Dinis-Ribeiro. 
·       Questions included is it cost effectiveness of doing 3-yearly surveillance to patients with OLGIM 4 changes – uncertain
·       Do we need to always sample or can we make an endoscopic diagnosis of intestinal metaplasia?  He claims that we can !  Mario quoted several papers in support of this: Pimentel-Nunes P. Endoscopy 2016;48(8):723-30, Castro R. Scand J Gastro 2019;54(11):1301-1305.) and Marcos P. Gut 2019
 
§  You may have come across ‘hereditary gastric cancer’?  You will suspect this if:
·       A pt develops diffuse gastric cancer before 40
·       2 family members with diffuse type gastric cancer.
·       history of diffuse lobular breast cancers
·       Pt has a cleft lip or palate
§  Of course the common syndromes are 1) hereditary diffuse type gastric cancer (pts have a mutation in the e-cadherin genes), Peutz-Jegherz syndrome and Juvenile polyposis syndrome (no strong link with FAP)
§  In pts with e-cadherin mutation targeted biopsies of any suspicious lesion as well as a minimum of 30 mapping random biopsies should be taken (the Cambridge endoscopy protocol).
§  Time-consuming, tedious process, which significantly prolongs the procedure and might reduce patient tolerance. In order to save time two specimens can be taken during a single passage of the forceps ("double-bite" technique).
§  II recall one such patient in Leeds
§  Now there was an abstract (P1138) on patients with ‘hereditary diffuse type of gastric cancer’ in which 51 confirmed carriers underwent surveillance. Both the endoscopist and the biopsies missed cancer in 23 pts.  If you exclude the cases when the endoscopist saw nothing but the histopathologist spotted the cancer in one of the <70 random biopsies (!), the miss-rate of endoscopy was 73% !!!  The authors concluded that either they needed to take more samples (1700 in fact) or surveillance simply doesn’t work in this group.  No shit !
 
5)      Barrett’s surveillance
§  Reminded us to always retroflex and have a look at the GOJ from below
§  Brushings (Wide Area Transepithelial Sampling = WATS, Vennalaganti GIE 2018;87(2):348-55) samples larger areas but requires AI to detect markers for dysplasia or for risk and takes an extra 4.5 minutes (pretty much doubles the duration of the examination). 
§  The recent Lancet paper by Rebecca Fitzgerald was mentioned; you may already be familiar with this paper which indicated that risk of future cancer could be estimated 8-10 years into the future by looking at number of cells with multiple sets of DNA
·       There was an update from Cambridge (A. Katz-Summercorn, OP016) who reminded us that there is no difference in the ‘gene copy number’ (the number of clonal mutations) between Barretts which progresses and does not progress to dysplasia and cancer.  Instead it was the ‘genomic heterogeneity’ which predicted risk of progression. Patients who progressed had a) more translocations whereby parts of chromosomes had broken off and re-attached itself at the wrong site, b) a larger number of mutations, c) ‘driver gene alterations’ (p53 mutations etc )
·       Unfortunately, the genomic heterogeneity’ changed in step with the dysplasia rather than before the dysplasia developed
·       Question arises of RFA can really be expected to ‘re-set’ the clock and if the same chromosomal translocations happens throughout our bodies as we age (from 30 translocations in the genome of an ‘indolent case of Barrett’s to ‘chromoplexy’ where more genes seem to be linking up with the wrong chromosome and finally ‘chromotrypsis’ where the genome is essentially ‘shattered’ and the patient has IMca.
·       Would it be expensive to do this ‘whole genome sequencing’ of DNA extracted from Barrett’s samples and give a single figure for the ‘genomic heterogeneity’.
§  We were reminded of the Dutch study published in Am J Gastro in 2010 by Curvers et.al. and subsequently by Duits (Gut 2014) that 9-13% of pts with Barrett’s LGD progress to HGD or IMca each year compared.  But that unfortunately, only 1:7 to 1:4 pts originally diagnosed with LGD was on review confirmed as actually having LGD.
·       We are supposed to have all diagnoses of LGD confirmed by an ‘expert pathologist’.  But how is this defined ???
·       Dr N Frei at Amsterdam University Medical Center reported (OP017) on the 155 pts with Barrett’s LGD who took part in the SURF Trial (remember this is the study which reported progression in 20% (34/155). Using a pathological immunohistochemistry stain and software called ‘tissue cypher)
·       8% of patients which ‘TissueCypher’ called ‘high risk’ progressed. 
·       My suspicion is that TissueCypher got it right and the pathologists got it wrong !!!
·       This was supported by the finding that a panel of 3 pathologists who reviewed the diagnosis of LGD in these 155 pts only agreed in 50% of cases and 1/3 of patients were downgraded as not having any dysplasia at all !!!
·       I was going to phone the pathology department asking them to purchase that ‘TissueCypher’ when I heard that everything hinges on the CORRECT histological slides being submitted for ‘TissueCypher’ analysis!
§  The basic question of which patient with reflux should be offered an endoscopy to check for reflux – remains unanswered.  Because about 15% of adults do have intermittent reflux and we are all overweight !
§  Should all patients with Barrett’s be started on a PPI. Roos’s answer was YES as there is evidence that it may reduce the risk of progression to dysplasia.  However, as far as I understand the risk of progression once you have already developed dysplasia is not affected by the use of PPI ?

6)      Surveillance to prevent Pancreatic cancer in high risk groups?
§  Obviously not for everyone but perhaps in high risk groups with: a) new onset diabetes, b) pts found to have a pancreatic cyst or c) those with a family history or a known mutation such as CDKN2A (mutation carriers get familial melanoma, glioblastoma and pancreatic cancers), BRCA1 or 2, MLH1 or MSH2 or MSH6 and pts with Peutz-Jeghers syndrome etc. It turns out that there is no evidence that regularly surveilling these patients saves lives. 


7)      Colorectal cancer
§  Polish study reporting that the lowest uptake of screening was in the countries where colonoscopy was done under propofol.  Actually, it was lowest in the countries were patients when straight for colonoscopy without a faecal test first.  The study found that those >60 yrs, living <20 km from screening centre and first having been offered a FIT were more likely to accept screening.
 
GI bleeding ·       Retrospective study of OVESCO clip vs angiography in Germany,           
·       1426 GI bleeding cases and only 128 pts were selected (highly selected)
·       Outcomes were similar in the over-the-scope clip group vs those who underwent angiography.  The only thing which was significantly different was the in hospital mortality which was higher in the angiography group – understandably !!!
·       We were reminded (IP155) of another prospective study of OVESCO clip in UGI bleeding, called the ‘Sting trial’ (Schmidt A. Gastroenterology 2018;155(3):674-86), in which 5 centres in Germany, Switzerland and Hong Kong recruited a total of 63 patients over a 3 year period who had re-bled from a peptic ulcer. 
1)      Half were then treated with ‘standard therapy’ (and which wasn’t standard as patients had adrenaline+clip as ONLY 2 pts had adrenaline+heat) vs the over-the-scope clip. 
2)      14/33 continued to bleed when their ulcer was re-treated with adrenaline+more clips vs only 2/33 in the OVESCO arm. 
3)      I have some concerns about the study:
§  In Leeds we published our experience on upper GI bleeding in 2016 and we had a total of 48 recurrent peptic ulcer bleeds over a 4 year period (End Int Open 2016;4:E282-6).  You would have expected these 5 centres to generate more than only 66 pts over a 3 yr period
§  In fact, you would have expected there to be twice as many in the study patients
§  I think that the authors may have been concerned at the onset that some ulcers may not be ‘suitable’ for the OVESCO clip as the initial protocol excluded patients with “endoscopic failure to reach the bleeding source”
§  That not every patient was randomised was also suggested by the fact that “All endoscopic procedures in each center were done by 1 to 2 experienced endoscopists”.  Is it really possible that 2 senior doctors were on-call for 24 hours, every other day for 3 years to be available when a patient suffered re-bleed ?
§  I am also concerned that the ‘standard’ treatment arm did not receive standard therapy
§  Finally, the study was not independent as the principal author received payment by OVESCO for consulting, lectures and research grants
·       An intermediate report on an ongoing prospective study (abstract P0041) from Korea of the use of a new haemostatic powder which they called ‘Nexpowder’ in patients with peptic ulcer bleeding.  11 patients (out of 70) re-bled after ‘standard dual therapy’ compared with 3 patients (out of 71) in the Nexpowder group.  I was going to make an order for that stuff when it was pointed out that actually half of the 11 patients who re-bled after conventional therapy ONLY had adrenaline injected into their ulcer.  It seems that the gold standard of ‘Dual Therapy’ for bleeding peptic ulcers is not commonly recognised in Korea.
·       Dr R. Inchingolo (IP069) reminded me of the Oakland score (Oakland K. Gut 2019;68:776-89) dividing patients with stable (=Shock index >1) with lower GI bleeding into high and low risk (includes age, sex, previous admission, blood on PR, HR – MOST important, systolic BP and Hb).  Patients  with PR bleeding and a shock index > 1 (HR/systolic BP) went directly to angiography.
1)      Patients with a shock index and an Oakland score of 8 or less was discharged (eg. A 70 yr old woman with blood on PR but with a heart rate of 70 and no hypotension and normal Hb). 
2)      My concern with the BSG guidelines is that patients with a higher score should be offered a colonoscopy at the next available list. In my experience it’s usually impossible for these elderly and frail patients to take sufficient prep for this colonscopy to be worthwhile. 
§  The BSG guidelines do admit that there ‘is no evidence for a benefit of colonoscopy’ in patients with lower GI bleeding.  Of course this is hard to deny as even a meta-analysis of the 4 randomised trials conducted (Tsay C et.al. Clinical Gastroenterology & Hepatology 2019 - https://doi.org/10.1016/j.cgh.2019.11.061), reported that there was no benefit in mortality (RR, 0.93; 95% CI, 0.05–17.21), diagnostic yield (RR, 1.09; 95% CI, 0.99–1.21), endoscopic intervention (RR, 1.53; 95% CI, 0.67–3.48), or any primary hemostatic intervention (RR, 1.33; 95% CI, 0.92–1.92) with early colonoscopy (<24 hrs) even in severe cases of lower GI bleeding.  Not surprising as about 95% of lower GI bleeding will stop spontaneously, 1/3 will rebleed once and ½ will rebleed a third time (Lim J. Tech Vasc Interv Radiol 2005) !!!
·       A very large study from India reported on the outcomes of 439 pts with moderate-severe radiation proctopathy.  Success was declared in 403/439 (97%) after only a few APC sessions.  Failure was linked with mucosal ulceration, >10cm long segment or >60% of circumference was involved.  However, there were 6 severe adverse events which included rectal perforations and recto-vaginal fistula.  There was a risk of strictures as well but this was not quantified.  Adverse events were linked with mucosal ulceration … However, the patients treated with APC was those who had failed sucralfate.  Sucralfate is still the mainstay of therapy, thank God. 
Therapeutics 1)      There was a session on oesophageal strictures where a few interesting points were raised:
§  A patient presenting with a food bolus obstruction and have features of EoE.  Would you carry out a dilatation at the index procedure?  The answer was no because topical steroids will usually have an effect within 3-5 days
§  How long can you leave a patient with a food bolus obstruction or if a battery is stuck in the oesophagus or even if it’s just laying in the stomach?  The ESGE guidelines say ≤6 hours
§  In some units the administer IV glucagon which supposedly have a 50% success rate.  Not recommended by the ESGE
§  A new device was mentioned called the ‘excavator’ – a plastic over-the-scope grasper
§  Of course what do try is first to push the bolus into the stomach and if this fails, try grasping with either a basket or perhaps a snare
§  Manning wasn’t keen on the use of an overtube and preferred a large flexible hood fitted to the end of the scope.
2)      Prof Inoue gave a presentation (IP017) of POET (Peroral Endoscopic Tumour Resection) whereby lesions attached to the muscle propria layer can be resected using a tunnelling technique.  Looking at his footage, I was reassured that Prof Inoue could point out the vagus nerve, the recurrent laryngeal nerve and other important landmarks to me.  Do I want to spend time dissecting nerves away from benign, submucosal lesions?
3)      The OVESCO clip has been used for full thickness resections in the upper GI tract.  In the stomach, R0 resection rates was 75%, complication rates was 30%.
§   When know that in the colon, full thickness resection is linked with a substantial perforation rate and an R0 rate of only about 70% and in lesions which are larger than 2cm it drops to 60%.  Therefore its recommended that only lesions up to 2cm should be considered for this.
§  Of course that staging MRI would have to be done before that clip is placed and that the TME plane will be difficult to assess if the patient goes on to further surgery.
4)      GERDx (Endoscopic Plicator) can be used to resect larger lesions <4cm in the stomach.  R0 resection in 85%
5)      An International Group was reached a non-controversial consensus on papillectomy (ampullectomies).  Contraindications included extension into CBD of >10mm. I would have put the figure lower because EUS usually underestimate this
6)      A French multi-centre study presented by Dr R Hallit (OP051) reported a 90% success rate treating early leaks with stents or pig-tailed stents.  No mention of ‘vacuum therapy’ !?
7)      Fortunately, in the same session there was a report (P. Stathopoulos OP052) of the immediate use of EVT in 9 cases of perforation (because the patient had swallowed something sharp or perforation complicating a dilatation).  Immediately placing a suction catheter in the oesophageal lumen closed all 9 defects within 1-3 weeks.  They replaced the sponge every 3 days but with the suction catheter placed within the oesophageal lumen, I don’t quite understand why this would be necessary?!
8)      Another study in 24 pts with gastroparesis (21 being female and only 6 had diabetes?!) all treated with G-POEM (Gastric Peroral Endoscopic pyloroplasty) in Holland (Conchilo JM OP055) reported some improvement in 14 pts and no improvement in 10 pts. There was no way of predicting who would improve.  The study group looked at the ‘pyloric distensibility index’ measured by ‘Endoflip’ or the ‘antro-duodenal manometry pattern’.  
§  Perhaps not surprising because delayed gastric emptying could be due to non-relaxation of the pylorus, or poor contractility of the antrum, slow transfer of food by the duodenum or perhaps relaxation of the gastric fundus.
§  A sham study is required next to prove that G-POEM is better than placebo
§   
Artificial intelligence ·       Fujifilm has CAD-EYE
·       Medtronics – GI Genius
·       Olympus – EndoBrain
·       Pentax – Discovery AI
·       There are others such as AI-Wision, Endo-Angel, Doc-Bot, AI4GI, NEC
·       4 Clinical Studies increased the polyp detection rate from 20% to 29%, 8% to 16% and 28% to 34% and 41% to 57%
·       Dr W Leung, Hong Kong (OP092) quoted 6 Studies have looked at AI to find EGC with accuracies ranging from 85% (in the largest study) to 96% (in the smallest study).  Of course, there has already been a meta-analysis of 6 studies which concluded that AI increases the detection of colonic polyps <10mm in size.
·       AI doesn’t increase the time it takes to do a colonoscopy, it’s not annoying to use but no evidence that is saves lives or reduce the risk of post colonoscopy CRC
·       Some simple things seem still beyond AI such as accurately measuring the size of a polyp (P1195, Dr Y. Mori) – although why not go one step further and the AI calculating the ‘polyp volume in cubic mm perhaps?!
·       Furthermore, they are not designed to eg distinguish a benign adenoma from a superficial cancer.
·       It’s also unclear if each AI system needs to be revalidated every time a new generation of endoscope is launched (would be crazy of course) or conversely, do you need to have version 2 of an AI software re-validated with a polyp video dataset (probably sensible).
·       Dr Mori also highlighted that the 5 or so AI systems which have been brought  to market have all been validated by their own dataset.  Who suggested that manufacturers should validate their systems with their freely available dataset of polyps consisting of some 1.5 million photographs (I presume from Showa University Hospital at Yokohama).
·       I’m hoping that it will help me as an Endoscopy unit QI lead to tell endoscopists, how many blind spots they leave, how often they forget to retroflex in the rectum, how often they don’t wash the bubbles and drain the puddles and how long they take to observe each segment of the colon.
·       They were lamenting that the AI don’t tell us what the polyps were but I don’t think that it matters because we need to remove all of them anyway !
Colonic Polypectomy ·       A meta-analysis of 71 studies of 5167 endoscopically treated T1 CRC from AMS reported that the overall risk of local recurrence was 1.6% (1.1% - 2.3%) and metastatic disease was also 1.6% (1.1% - 2.4%) usually within 6 yrs of resection.  Histology was the strongest predictor of risk and patients with ‘high risk’ histological features had a 7% risk (5-10%).  Oddly enough there was no agreed definition of what a histological high risk T1 cancer actually was?!   40% of those who developed a recurrence died.  Polypoid vs Flat cancers, single fragment vs piecemeal resection did influence risk of recurrence but was less important than histology.
·       A study from France (P1193) did report on 353 pts with T1 CRC and reported that 16% did have lymph node mets and it was when the margin clear of cancer was >2mm and when there was no LVI, poor differentiation or extensive tumour budding). 
·       There is data coming out of Japan and our screening programmes that if SM3 invasion is the only risk factor, then the risk of LN disease is probably ≤3%.
·       Yutaka Saito (IP068) updated us on the JNET (Japan Gastroenterological Endoscopy Society) that there is no need to place a clip after cold snaring as the risk of late bleeding was tiny (2/429 pts 0.5% ie.  We would have to spend about £6-7000 on clips to prevent 1 late bleed but in Japan when a clip only cost €7, you would only have to spend £1400 to prevent one case of late bleeding.  Unless of course, the patient was on antithrombotic therapy, (anything stronger than aspirin). 
o   There is no JNET guideline on the prophylactic clipping of EMR defects but Yutaka Saito does believe that this reduces the risk of late bleeding, particularly in pts on antithrombotics.  Of course after a large ESD, closing the whole defect can be difficult, nevertheless, they will always place clips at the National Cancer Centre
o   He also suggested that warfarin could be substituted for a DOAC rather than with LMWH which is what we usually do in the UK. As the DOAC only needs to be withheld on the day of the procedure.
o   Prof Saito was asked when he would restart a DOAC after a large EMR. Of course in Japan, all these patients are in hospital for a 3 days after an EMR (and 1 day before). It turns out that if the nursing staff don’t report any bleeding, the DOAC would be restarted 24 hours after EMR
o   As regards dealing with immediate bleeding, he recommended using forceps as clips would get in the way, and to deal with pulsative (arterial) bleeding straight away.
·       Dr T Kuwai, Hiroshima (P1185) presented a study comparing ESD using a needle type knife with scissor type knives finding that the scissors were safer but slower to use.  However, the study was a retrospective analysis and of course not randomised.  Nevertheless, I’m sure that it’s true.
·       Dr Dhillon from St Mark’s presented data (P1189) on the use of Scissors in removing large sessile polyps.  Out of 61 polyps, 1 could not be removed and there was 1 local recurrence at 1 yr (but 31 pts had not yet had their follow up).  In 20% there was some intraprocedural bleeding but no perforations.
·       A GI histopathologist from France (IP148) reminded us not to take samples from possibly malignant polyps because when the polyp is subsequently resected endoscopically, the inflammation, and displacement or destruction of glands may mimic invasive cancer and even LVI (Panarelli NC. Am J Surg Pathol 2016;40(8):1075-83).  Naturally, we were also reminded that they struggle excluding invasive cancer in polyps harbouring HGD.  But presumably it would not stop them from making a diagnosis of intramucosal cancer, which would be a step in the right direction.  Histopathologists don’t like estimating ‘tumour budding’ as inflammation makes it difficult to assess.  Of course pathologists don’t like to estimate depth of submucosal invasion as they can’t see the muscle propria.  Finally, I was surprised to hear that there is uncertainty whether LVI should be assessed on H&E only or after immunohistochemistry. 
·       There was a presentation (IP156) on the topic of stopping and starting anti-thrombotic therapy before endoscopy.  The ‘Bridge trial’ from 2015 was mentioned (Douketis JD. NEJM 2015;373:823-33) a double blind randomised prospective study in which 900 pts had their warfarin stopped and another 950 received LMWH instead.  There were to 2 strokes and 2 TIA’s in the placebo group and 3 strokes in the LMWH group.  However, the average CHAD2 score was only 2 and simply stopping the warfarin (or perhaps not starting it in the first place) is now standard therapy.  Dr Braun recommended restarting a warfarin the day after the therapeutic procedure and a DOAC two days after.  Yet another reason to place lots of clips!!!
Colonoscopy ·       A Danish study (OP027) looked at Post Colonoscopy CRC .  The risk of a Danish patient being diagnosed with CRC within 3 years of their colonoscopy was 0.2% comparted to 0.7% in pts without IBD.  This is lower than both in Sweden and in the UK.  It seemed paradoxical but the risk of being diagnosed with a CRC increased with the number of colonoscopies the patient underwent in both patients with a without IBD ?!   Turning the figures on it’s head, 24% of IBD patients with CRC had undergone a colonoscopy in the preceding 3 yrs compared with 7.5% of non-IBD pts.
·       A study from Poland presented by P. Wieszczy (OP101) also confirmed that endoscopists with the highest ADR or highest ‘Polyp Detection Rate’ had half the risk of PCCRC.  Matt Rutter asked why the study excluded patients with the worst prep? 
·       A multicentre Spanish-Dutch Study looked at Lynch Syndrome patients (OP102) who had undergone 4000 surveillance colonoscopies over 5 yrs.  Of the 893 Lynch syndrome pts, 48 developed cancer (5.4%) and the PCCRC rate was 8% (5.2-10.6%).  Colonoscopy quality indicators did not correlate with the risk of cancer but undergoing a surveillance colonoscopy with a shorter interval than 3 years was found.  Fortunately, both the ESGE and the BSG recommend surveillance every 2 years!  
·       In the discussion, the usual complaint popped up when surveillance was found to be wanting: we need to do it more often, only specialists should do it, only the best endoscopes should be used, the bowel cleansing need to be brilliant or why not go the full way and accredit a few centres who are accredited to do the surveillance. 
·       Dr S. Semenov in Dublin (OP096) mentioned the FIT study (Cross AJ. Gut 2019;68:1642-52) where nearly 6000 patients with ‘intermediate risk polyps’ were offered annual FIT tests to see if this could predict who had advanced adenomas or cancer.  As you probably know, the use of FIT rather than colonoscopy would miss 30-40% of cancers (12 CRC’s in 5019 pts) and 40-70% of advanced adenomas (295 advanced adenomas in 5010 pts).  
o   Anyway, this Irish study of the use of colon capsule (costing €500 each) reported a reduction in need for a endoscopy by 40% and that colon capsule was better than FIT in predicting patients with polyps.  Surprising perhaps that all of the colon was only seen in 70% of patients as they often got stuck in a diverticulum until the battery run out or the prep was terrible.
·       There were a couple of presentations from the mainly the first and second round of the Dutch Bowel cancer screening programme (OP and OP104) reporting that there was a 91.5% caecal intubation rate, 100% achieved an ADR of at least 30% (of course most found far more adenomas – in the 60-70% range but the ADR was a little lower in colonoscopists carrying out <200 procedures/year), the ‘polyp removal rate’ was 97.4% (I call this the polyp ‘attack rate’ and in Leeds this is 89%), and 91.5% of 387 colonoscopists did take at least 6 minutes to extubate.  Surprisingly, they were also audited on the adequacy of their patients prep and 100% achieved ‘good enough’ prep.  There was also an overall bleeding rate of 0.51% and perforation rate of 0.06%
Barrett’s ·       A study from Utrecht reported that about 10% of patients undergoing RFA for unstable Barrett’s responded poorly and healed slowly. Eventually, half of these responded whilst the other half was left healed but still with Barrett’s. Risk factors included those with more reflux (obese men with longer Barrett’) or those with the most severe dysplasia.  There is no strong evidence that swapping to cryotherapy would lead to better outcomes.  For the fatties, you could consider a Nissen’s fundoplication.  In Leeds, we usually end up keeping the elderly patients under 3-6 monthly surveillance, EMR’ing lesions as they develop. 
·       Prof Messman mentioned a meta-analysis of 6 studies of cryotherapy (IP146; Hamade N. Dis of the oesophagus 2019;32:1-10)  which reported a failure rate of 30% (very similar to RFA studies which gets better as experience builds) and a stricture rate of 5%.  On the upside, the kit will probably be cheaper than RFA and there was less pain afterwards than with RFA
​
·       Incidentally, I anticipate poor outcomes with RFA if there is no neo-squamous mucosa at the site of previous EMR’s.
·       In Leeds, we don’t offer RFA to Patients who have undergone oesophageal radiotherapy in the past as we have had particularly poor outcomes in these patients
·       A study from the ‘Dutch Barrett Expert Centres (presented by Dr E. Nieuwenhuis, P0154) followed 120 patients who had been found to have invasive cancer within their EMR specimen.  The divided their patients into 3 groups:
o   55 pts invasive cancer not invading any deeper than 0.5mm into the submucosa – only 1 pt developed mets
o   27 pts with still only intramucosal cancer but with either poor differentiation or LVI – surprisingly 6/27 (22%) developed mets – all 6 pts had LVI. 
o   Oliver commented that also in their cohort no patient with intramucosal cancer and poor differentiation developed metastases
o   In 38 pts with invasive cancers, going even deeper and with poor differentiation and/or LVI there were (surprisingly) only 2 patients who developed mets
o   As expected, most patients died from causes other than their cancer during follow up.
·       Dr Pouw mentioned the ongoing multinational ‘Prefer study’ in which patients with invasive Barrett’s cancer going no deeper than 0.5mm but with poor histological markers are not sent for surgery but are kept under close observation for 5 yrs with 3-monthly OGD+EUS for 3 years and then every 6 months for another 2 yrs ( a total of 16 gastroscopies and 16 EUS examinations) . 

 SESSION 1: AI for automation in endoscopy and surgery (3)
 1.      State of the Art and general perspectives on AI/ D. Stoyanov, UCL

AI can be useful to solve 3 types of challenges:
1.Navigation: within environment, shape of lumen, identify anatomy
2.CAD: computer aided detection (CADe).. mature tech, regulatory approval, available for clinical use
3.CAD: computer aided diagnosis (CADx)… emerging tech
 
Examples of AI in endoscopy:
■  CADDIE – Odin Vision Ltd, start-up... polyp detection software.. rectangle drawn around polyp. The system uses real time machine learning algorithms to analyse colonoscopy images and support doctors to identify and characterize polyps during colonoscopy procedures. The system is cloud deployed and has the capability to scale across the whole of the NHS.
 
■  Showed an abstract concerning polyp segmentation using a hybrid 2D/3D CNN (Convolational Neural Network) .. evaluated in 46 patients with 53 polyps, 560000 image frames…. Superior to normal spatial model

(The term “convolutional neural network” indicates that the network employs a mathematical operation called convolution. Convolution is a specialized kind of linear operation. Convolutional networks are simply neural networks that use convolution in place of general matrix multiplication in at least one of their layers).
 
■ Apart from polyp detection, speaker also showed software which can detect various upper GI structures in an endoscopy video: He et al 2020: Deep learning based anatomical site classification for UGI endoscopy
This AI is trained to run over a video to make sure that predefined sites have been recorded.
 
■  Also showed software which estimates 3D shape of environment and how camera moves within it…. fly through simulation.
 
Q&A session:
Q. Pilcam and AI: reduce time to analyse… use AI as support tool, still need Dr to check. Small bowel may be ideal place to use AI to reduce analysis time.
Q. Automation of resection (EMR, ESD etc)?... detection of polyp can be done, far away from resection.
Q.  AI fitting into clinical workflow?....  supportive tool
 
 
2.      Exploring autonomy in Robotic Colonoscopy/ P. Valdastri from Leeds (Chair in Robotics and autonomous systems, director of STORM)
 
General discussion on  autonomy:
Refers to an editorial in Science Robotics (Yang et al 2017) which defines various grades of autonomy :
https://robotics.sciencemag.org/content/2/4/eaam8638.full
 
no autonomy… robot is operated by surgeon eg da vinci robot assistance.. task autonomy… conditional autonomy… high autonomy… full automation
Level 0: No autonomy. This level includes tele-operated robots or prosthetic devices that respond to and follow the user’s command. A surgical robot with motion scaling also fits this category because the output represents the surgeon’s desired motion.
Level 1: Robot assistance. The robot provides some mechanical guidance or assistance during a task while the human has continuous control of the system. Examples include surgical robots with virtual fixtures (or active constraints) (2) and lower-limb devices with balance control.
Level 2: Task autonomy. The robot is autonomous for specific tasks initiated by a human. The difference from Level 1 is that the operator has discrete, rather than continuous, control of the system. An example is surgical suturing (3)—the surgeon indicates where a running suture should be placed, and the robot performs the task autonomously while the surgeon monitors and intervenes as needed.
Level 3: Conditional autonomy. A system generates task strategies but relies on the human to select from among different strategies or to approve an autonomously selected strategy. This type of surgical robot can perform a task without close oversight. An active lower-limb prosthetic device can sense the wearer’s desire to move and adjusts automatically without any direct attention from the wearer.
Level 4: High autonomy. The robot can make medical decisions but under the supervision of a qualified doctor. A surgical analogy would be a robotic resident, who performs the surgery under the supervision of an attending surgeon.
Level 5: Full autonomy (no human needed). This is a “robotic surgeon” that can perform an entire surgery. This can be construed broadly as a system capable of all procedures performed by, say, a general surgeon. A robotic surgeon is currently in the realm of science fiction.
 
Speaker showed demonstration of the Magnetic Flexible Endoscope (MFE): originated from European project 2010. Magnetic coupling is used to pull the tip of the endoscope… reduce trauma… likened to “front wheel drive” endoscope. The body of the scope does not need to be stiff because it is being pulled. Device has illumination module, camera, irrigation nozzle, instrument channel.
 
In early studies (Arezzo et al 2013), user controlled external magnets with joysticks in model of colon ex vivo: navigation and diagnostic accuracy comparable to standard colonoscopy but robotic procedure was 3x slower!
 
System was enhanced with Real-Time Pose/Force Detection which allowed it to  sense in real time the position of the tip of the scope.
 
1st level of automation: robot supervised tele-operation: user is controlling tip of endoscope with joystick in a model looking at the image on a screen. 4 way movement. Like driving a car… the robot decides how to move the magnets in response to joystick movement.
 
2nd level: task automation
-e.g. autonomous retroflexion. At press of button, system computes best trajectory for retroflexion and moves external magnets. Pig model. 100% success in pig models, task takes average of 11 sec.
-autonomous microUS imaging: animal experiments
 
3rd level: autonomous navigation with lumen detection (Martin et al 2020)
non live models used: average time to caecum 4 min, 10 users, 5 reps each, 100% success. System identifies lumen for image and direct tip in that direction.
Validated in pig animal model. Could navigate to up to 85cm into colon.
 
Q&A session:
Q. Magnets pull from front of tip = front wheel drive (cf rear wheel drive for normal colonoscopy)… so the body of the scope is very flexible… “looping will be negligible”, less force used, less pain thoretically.
Q. How to handle peristalsis?: lumen is insufflated, “peristalsis is not a problem”
Q. Sharp flexure/ angulation?: “able to navigate pretty sharp bends” with magnets + insufflation
  
3.      Lower GI polyp detection and differentiation/ A. Repici, MILAN
CRC cancer increasing in USA, EU etc.
Adenoma may be missed in 27%
Adenoma detection rates varies a lot in Italy 1.7% - 36.8% (Zorzi 2017… 50K colonoscopies)… threshold is 20%.
 
Colonoscopy is an imperfect tool: missed polyps, interval cancer, ADR variability among operators, heterogeneity is histology prediction.
Human factors: skill, dedication, image interpretation, frame capture, speed of analysis
 
AI Universe in endoscopy:
-Fujifilm: CAD-EYE  *
-Medtronic: GI-Genius *
-Olympus: Endobrain
-Pentax *
-AI-Wilson
-Endo-Angel *
-Doc-bot
-AI4GI
-NEC
 
SESSION 2: Will AI change our practice in endoscopy 
1.     Moderated poster/ Y Mori: Japan/ Oxford/ Norway/USA
Looked at economic benefits of AI in colonoscopy.
Study was an add on analysis of a clinical trial (Ann Intern med 2018) that investigated performance of AI in differentiating colorectal polyps (neoplastic vs non- neo). >90%PPV in rectosigmoid. Included all patients with diminutive (<=5mm) rectosigmoid polyps for analysis.  N=250

Two scenarios analysed: 
A: diagnose and leave strategy supported by AI (ie AI predicted non neoplastic polyp). 
105 polyp removed, 145 polyps left
B: a resect all polyp strategy
250 polyps removed, no polyps left
 
Strategy A reduces cost by 7-20% depending on country= millions of dollars/ year
Conclusions: AI and diagnose/leave saves money.
 
Study subsequently accepted for publication in GIE journal, October 2020 issue (youtube video).
 

SESSION 3: AI: abstract-based session (3)
1.      Size Matters: is AI using computer vision better than human humans in sizing colonc polyps?/ Mo Abdelrahim…P Bhandari/ Portsmouth + Japan
 
Polyp size is important biomarker
-          Related of risk of dysplasia/ adenoca
-          Therapeutic implications… eg resect and discard
-          5mm cutoff is important
-          hard to estimate polyp size 
Aim: to develop automated system for binary classification of polyp size. 
              To compare its performance to that of endoscopists at various levels of experience
Method: artificially made premeasured polyps fixed in pig models
Then colonoscopy of pig colon done and recorded
Computer Vision (CV) used

Q&A 
Computer Vision is technology used… not deep learning…
Structure for Motion = algorithm used…3D image constructed from 2 D image using triangulation.
 
 
2.Machine Learning Models for the Prediction of Risk of gastric cancer after HP eradication therapy/ W. Leung, HK, China
 HP is class I gastric carcinogen, risk of GC at least 2x in HP infected individuals.
Hp eradication reduces cancer risk by 46%.. but some will progress to GC even after HP erad
Deep machine learning used to predict GC risk after HP eradication.
Training set (64k) and Validation cohort  (25k)of patients
26 clinical variables used in models
Outcome development of GC within 5 yrs of HP eradication
7 different algorithms analysed.. ROC for each


3.Unexperienced endoscopists can reach expert level in detecting and characterising colorectal polyps by using a validated detection and characterisation system/ J Weight
 Strong need to increase ADR (to reduce risk of cancer)
Still 1/5 polyp is missed in colonoscopy
Fujifilm developed CAD Eye to detect and characterise polyps
Aim: to  evaluate above system for polyp detection and characterisation.
Methods: 4 centres:Magdeburg, Milan, Rome, Mainz
Eluxeo Series Fujifilm (700)
Annotation according to findings and histology
Development of CadEye system

Gives likelihood of neoplastic or hyperplastic polyps
Validation of CAD Eye system on still images
              3 experts and 3 beginners
              experts alone vs non experts + CadEye
              Detection: 458 WLE images, 455 LCI images
              Characterisation: 133 WLE, 134 BLI images
Images presented for 5 seconds

Conclusions: new system has impact on adenoma detection and correct classification of polyps. Beneficial for non experts. Experts may also use
Weakness: no comparison without CadEye (increase?)
Trials re planned for real time use in clinical settings.
 
SESSION 4: Beyond our Eyes: AI enhanced endoscopy (5)

1.      DEVELOPMENT OF AN ORIGINAL AUTOMATED METHOD OF THREE-DIMENSIONAL RECONSTRUCTION OF AN EXTENDED FIELD OF VIEW OF THE GASTRIC ANTRUM by T. Bazin/ France
 
Problem: detailed description of digestive mucosa by endoscopy: lack of inter and intra observer reproducibility
>3D reconstruction of a mucous surface from endoscopic images
              reproducibility
              reinterpretation over time
Ø  No method of extending the 3D fov has been described for the digestive tract
 
Aim: use AI algorithm to reconstruct extended detailed 3d field of view of antrum using recording of endoscopy in WL and BG light.
8HD videos used to train the system (Olympus)
correction of camera distortion
reconstruction of mucosal surface involved 3 stages: complex calculations… point cloud is use dto build mesh surface
Fully automated method.. can deliver 3D surface of antrum about 1 hour after the end of recording
Obtained precise 3D reconstruction of surface of antral mucosa
 
Pradeep Bhandari asked about clinical value of this system… vague answer
Resolution may be limited.. working on higher res

2.      HIGHLY ACCURATE AI SYSTEMS TO PREDICT THE INVASION DEPTH OF GASTRIC CANCER: EFFICACY OF CONVENTIONAL WHITE-LIGHT IMAGING, NON-MAGNIFYING NARROW-BAND IMAGING AND INDIGO-CARMINE DYE CONTRAST IMAGING by S. Nagao/ Tokyo

Gastric cancer (GC) is 2nd or 3rd leading cause of cancer related death in world
High S5yr among patients with early GC
Early GC is good target for endoscopic resection… early detection important

Macro features and eUS not very accurate in diagnosing early GC.

Previous reports (Zhu et al and Yoon et al) : accuracy of AI 0.8916/ -, PPV 0.8966/ 0.780, NPV 0.8897 /0.793 
This study: aim was to develop new AI systems to more accurately predict dept of invasion of GC
 
60000 images collected from 1800 cases of GC for which oncosurgery was performed
Cases randomly assigned to training or ? 4:1 ratio
AI looked at images using WLI NBI and indigo and output a probability score for invasive cancer

Results:
baselines characteristic similar

?definition of correct diagnosis: if >=5/10 images of same lesion were correctly diagnosed – then diagnosis was “correct”

3.      USEFULNESS OF THE ALGORITHM OF ALL-IN-FOCUSED IMAGES IN IMAGED ENHANCED ENDOSCOPY FOR COLORECTAL NEOPLASM by T. Yamamura/ Nagoya, Japan
Magnifying endoscopy is useful in assessment of invasive depth in colorectal neoplasms with image enhanced endoscopy (IEE).
Some part s of the image may be in focus and other parts out of focus because e of the depth of the target + peristalsis 

AIF algorithm puts many images together to make one image is fully in focus, (surface pattern), vessel pattern and recognition of diagnosis (JNET classification), pit pattern: all scores improved with AIF
Not much diff in decision time No sig diff in accuracy
Technique may be of benefit for the beginner.
Lag in processing of image = 30 secs, with increased processing power, may be possible to process image in real time.
 
4.      DEVELOPMENT AND REGULATORY APPROVAL OF AN ARTIFICIAL INTELLIGENCE-ASSISTED DETECTION SYSTEM FOR COLONOSCOPY by T. Matsuda/ Tokyo and Nagoya, Japan
Colon polypectomy reduces CRC mortality: 53% over 20yrs
ADR is a quality indicator for colonoscopy 22%
 
Currently some CADe systems are available in EU: GI Genius (Medtronic), Discovery (Pentax), CAD Eye (Fujifilm).. all approved in EU
Authors have developed CAD system and have obtained regulatory approval.
FIRST officially approved AI system in Japan.
Lot of small polyps in dataset
?efficacy of AI picking up SSL and NGLST
Colitis patients were excluded
 
5.      ARTIFICIAL INTELLIGENCE USING CONVOLUTIONAL NEURAL NETWORKS FOR DETECTION OF EARLY BARRETT'S NEOPLASIA by M. Abdelrahim/ Portsmouth and Tokyo
Incidence of Barrett’s neoplasia has risen in recent years.
Early detection is key to improve prognosis
Early Barrett’s neoplasia can be difficul to detect during endoscopy
Hence quadrantic bx: expensive, time consuming, miss rate
This talk: on detection and delineation of Barretts mucosa
Aim: develop and validate a deep learning system for detection and delineation of Barrett’s neoplasia
Method: data collection: 
-621 HD white light images on neoplastic BE from 43 patients
-23183 images/frames of non neoplastic BEW from 44 patients
- histologically confirmed
Data interpretation: 
-          Marked and annotated using specially designed software
-          Review by 2 expert

Data divided into 3 subsets which were used for training, validation and testing ofr  the system
Visual Geometric Group architecture for binary classification
SegNet architecture for delineation
Speed very fast compared to human visual response
For segmentation, a metric called IoU (intersection of union) was used: measures overlap between correct position and estimated position
Good results but room for improvement.
Hot spot on right where lesion is
Can also delineate more subtle lesions.. impressive
Delineation Works in real time
 
Conclusion:
High sensitivity, specificity and accuracy
Ultra short processing time
Needs validation on larger scale real time studies
Q: HD white light use din this study. Maybe indigo , NBI may assist the AI
Q: AI in training? Yes, AI will help trainees. Will AI make people lazy?!