How long have I got doc?

This gastric lesion is found in an 85 yr old man. Samples have confirmed a moderately differentiated gastric cancer but the lesion can't be seen on CT. The patient is frail with multiple comorbidities and declines both an endoscopic resection and surgery.  However, he does ask how long it will take before he dies from the cancer?
WHAT WILL YOU ANSWER?

a) 1-2 yrs

Definitely too pessimistic!

b) 2-3 yrs

Hmm, perhaps if the lesion is poorly differentiated but it doesn't look it!

c) 3-4 yrs

This is probably how long it will before that cancer is at an advanced stage but patient will probably survive for another couple of years beyond that 'transition point'

d) 4-5 yrs

Probably too pessimistic still!

e) >5 yrs

With limited information this is the only figure backed up by some data.

Explanation

This question is something of an homage to Sir David Cox who developed the well known 'Cox Regression analysis'. Professor Cox died in 2022. As you know, the 'Cox Regression analysis' basically explores the relationship between the length of survival and more than one variable. 

You would expect the following 'variables' to influence cancer-specific survival; histology, size of lesion, stage of lesion and perhaps the macroscopical type of early gastric cancer. Perhaps the location within the stomach also influences survival. There is some data that lesions at the gastric cardia are worse. 

Of course we don't have data on any of these 'variables'.  However, I know of one paper by Tsukuma et al [Gut 2000;47(5):618-21] which did look at the natural history of 56 early gastric cancers in Osaka, Japan. This paper was actually a riposte to an earlier editorial from Leeds by one of my colleagues arguying that EGC is a 'pseudo-disease [Everett S. Lancet 1998;351:1350–2]. 

As you would expect, 56 EGC's is not enough for any sub-analysis of the above variables. Also they didn't actually look at survival. They looked at the average time it took lesion to progress from what appeared to be 'early' gastric cancer (i.e. confined to the mucosa or submucosa) as diagnosed by endoscopy. 

And here we reach the first issue! How sure can we be that the lesion in the image is an EGC and hasn't started to invade into the muscle propria (thus being advanced)? The lesion is about 2cm across and there is a an organised crypt pattern in the centre (can't comment on the vessel pattern as there are no magnification images). It does look 'early' and I stand at least an 80% chance of being correct in that diagnosis. Incidentally, 'lifting' is not a reliable sign in the stomach as any ulceration of the mucosa will tether it down, regardless of stage of invasion. 

The authors were pleased to report that if patients are left for long enough, those EGC's will grow and progress.  No surprise there then!  But the rate of progression was slow!!!  The median time it took for 'early' gastric cancers to progress to advanced gastric cancers (i.e. T2 or worse) was estimated to be 44 months but probably shorter in patients with poorly differentiated cancers. Furthermore, the cumulative 5 year corrected survival in patients who never underwent surgery was about 63%.  

The answer to the question is therefore 'e'.  This patient is likely to live more than 5 years from diagnosis of his early gastric cancer.  Better than expected here is the Kaplan-Meyer curve below !