This was found at the caecal pole in an 75 yr old man. Two years ago, a small adenoma had been removed from this spot.
WHAT WOULD YOU DO NEXT?
■ Ignore the lesion
Perhaps reasonable if patient is unlikely to live more than a few years
■ Keep under surveillance
Reassuring to everyone but may seem ridicilous if patient is turned down for a resection at the age of 80, following 3 heart attacks and a stroke ...
■ Attempt another EMR
Very unlikely to succeed if original resection was done by someone with experience
■ Attempt a full thickness resection
Don't you need further information before deciding?
■ Refer surgically
Uncertain as not studies have compared endoscopic vs surgical approaches
The crux of the problem is two-fold: First, what is the risk that this lesion will turn cancerous and kill the patient and second what would be the risks of its' removal.
• It's a little below 10mm in diameter and according to the data from the NHS BCSP, the risk of cancer within the lesion would be 1.5%. You could perhaps argue that it may be a little greater because it's a local recurrence. On the other hand the surface biopsies had been reassuring only showing a TA+LGD and this probably reduces the risk closer to 1%.
The risk of the polyp turning cancerous in the future in the main depends on how long the patient lives. A Norwegian study by Eide T et.al. (Int J Cancer 1986;38;173–6) put the annual conversion rate to cancer for an ‘average’ colonic polyp at 1.25% at 5 years, 2.5% at 10 years and 5% at 20 years. A barium enema study (Stryker S. et.al. Gastroenterology 1987;93:1009–13) of polyps larger than 1cm, estimated the risk of cancer to be 2.5% at 5 years, 8% at 10 yrs and 24% at 20 years. There is also a CTC study of 306 polyps in which only 6% of polyps in 6-9mm range grew larger than 10mm at an average follow up of 2.3 yrs (Pickhart PJ et.al. Lancet Oncol. 2013;14(8):711–20). My own rule of thumb is that if the patient has a life-expectancy below 10 yrs, there may be little to gain by prophylactically removing lesions. This also fits with the latest UK postpolypectomy surveillance guideline which suggest that it should only be offered in patients with life-expectancies greater than 10 yrs (Rutter M et.al. Gut 2020;69:201-23). There are life expectancy calculators available online (just click the link).
• As regards 'risks of removal', at one end of the spectrum you have the risks of an 'average colonic polypectomy' (for a subcentimetre polyp. I usually quote a ≤1:200 risk of late bleeding and ≤1:1000 risk of a perforation). Not all polyps are the same and at the other end of the risk spectrum, you have the risk linked with an 'ampullectomy/papillectomy'; 1:10 risk of acute pancreatitis for up to a few months after the procedure, 1:10-20 risk of late bleeding for up to 2 weeks after the procedure, 1:50 risk of a perforation, a 1:10 risk of late stenosis, 1:20 risk of acute cholangitis and a 1:200 risk of death ...
• So what can a full thickness resection offer? A recent retrospective review by Ichkhanain Y et.al. from 18 centres (12 in the USA, 5 in Europe and 1 Canadian centre) reported on 66, young fit patients with smallish lesions (avg size 15mm). Surprisingly, 26 of the 66 lesions did not extend deep into the appendix lumen and arguably could have been removed by conventional EMR !? The authors don't elaborate and probably didn't have any further information than that 14/66 lesions had failed a prior attempt at conventional resection.
90% of patients were given prophylactic antibiotics and everyone was admitted after the procedure. Most (70%) of procedures were done under propofol anaesthesia but that is probably the normal approach in the US. The average procedure time was 1 hour. The overall chances of a completely successful endoscopic clearance was 75% (50/66). As regards complications, 17% developed appendicitis (10/58) and 6 pts these patients required surgery. I presume that the appendicitis was rather severe in these cases as patients staid in hospital for an average of 5 days following their surgery! The prophylactic antibiotics did not seem to make any difference to the risk of appendicitis.
The success rate of 75% doesn't compare all that well to the reported success rates of ESD which was 95% but that study was small with only 34 cases (Jacob H et.al. Endoscopy 2016; 48: 829-36).
• What can your surgeons offer? Insertion of a straight stapling device across the caecal pole whilst pulling on the appendix would probably be a quick surgical procedure without any risk of post procedural appendicitis and a 100% chance of complete clearance. Of course it would be more expensive and the usual hazards associated with a GA and surgery would be in play.
By the way, Michael Bourke at Westmead Hospital in Australia writing in Gut 2021;70(2) points out that the surface area of the appendix constitute 7% of the caecal surface area. You will be familiar with a similarly sized triangle of mucosa between the two ends of the ileo-caecal valve and the appendix - the so called 'lawyers triangle' (for obvious reasons)?
Michael highlights a study of 34 patients with the 'Serrated Polyposis Syndrome, serrated lesions was found in 23 and some were dysplastic (Pathology 2016;48:30–4). Unfortunately, the single most important fact is missing - what proportion of patients with 'Serrate Polyposis Syndrome' actually develop cancer of the appendix?
To summarise, I don't think that it's possible to give a 'correct answer' for this question. The 'correct decision', would depend on the patients life-expectancy, the histology of the polyp (HGD would push you towards resection of course) and whether there is anything to suggest that the patient would not 'do well' if he/she developed severe appendicitis requiring emergency surgery afterwards.