This subcentimetere polyp was discovered in the rectum of a 60 year old woman undergoing a bowel cancer screening colonoscopy following a positive FIT. Considering the endoscopic appearance and the degree of lifting,
WHAT WOULD YOU DO?
■ This is a benign adenoma but it's too close to a large vein for removal
Don't worry about the vein!
■ This is a benign adenoma which I would remove
Doesn't look benign!!
■ This is a likely early cancer which I would remove
Yes it looks evil but should you attack?
■ This is an invasive cancer which I would only sample
Can't argue with that!
That vein looks intimidating but don't be intimidated! It's not a 'show stopper'. it will move out of the way. However, that polyp does look nasty as there is no definite crypt pattern in the centre, just a swirly surface. However, the lifting is good, suggestive that we stand a good chance of clearing the lesion endoscopically ...
And at this point you can either go ahead and remove the likely early cancer. The advantage is that you get the correct diagnosis whilst biopsies are often inconclusive. The reason why surface biopsies are often unable to confirm invasive cancer is because your pathologists rely on seeing invasion of malignant tissue below the muscular mucosa. The underlying muscularis mucosa is usually NOT included in surface biopsies.
However, this is a good example of the potential disadvantages of going ahead to resect the lesion. As you'll see in the video below, I removed it. Histology reported that the lesion was indeed an early rectal carcinoma, 6mm in diameter and with clear margins. However, the deep margin was 'only' clear by 200 microns which of course our pathologists would call a 'positive deep margin'. A 1mm (that is 1000 micron) is the 'accepted' definition of a 'clear surgical margin'. Secondly, there was of course a small focus of LVI. There is usually something to keep you awake at night after removing an early cancer.
The disadvantage is obviously that you don't know what to tell the patient!!! - Is my cancer gone or not? - I'm sorry but I'm not sure! - Couldn't you keep a close eye on me with regular colonoscopies and CT's? Well, we could but there is absolutely no evidence that this will save your life IF you still have cancer cells inside of you...
Fortunately, there is a study under way in the Netherlands to answer this very question! At the moment, we know that LVI is 'bad' and that the normal next step would be to offer the patient surgery.