WHEN considering follow-up colonoscopies after non-advanced adenoma, guidelines are a helpful starting point, but doctors should always make an individualised assessment of each patient, say colorectal and gastrointestinal experts.

The experts were commenting on research published in the MJA which questions the decision to recommend a surveillance time frame of 10 years in some patients.

The guidelines of surveillance intervals following removal of low risk conventional adenomas changed from 5 to 10 years in 2019. Some in the field wondered whether there was strong enough Australian evidence to back up this decision.

“We felt like it would be reasonable to look at these data that we have in our surveillance colonoscopy program, and see if expert consensus was actually backed by the data that we have,” research author Dr Zaki Hamarneh explained to InSight+.

Hamarneh and colleagues retrospectively analysed data from patients enrolled in a South Australia surveillance program who had findings of non-advanced adenoma from 1999 to 2016 and subsequently underwent surveillance colonoscopy.

“The estimated incidence of advanced neoplasia at the follow-up colonoscopy was 19% at 5 years and 30% at 10 years after removal of a non-advanced adenoma,” the study found.

The authors wrote that the acceptable risk of advanced neoplasia at surveillance colonoscopy was generally regarded as 10–15%.

“Our findings suggest that extending the surveillance interval beyond 5 years markedly increases the risk of advanced neoplasia to levels higher than currently regarded as safe, regardless of the definition of advanced neoplasia applied,” the authors wrote.

However, Dr Karen Barclay, a colorectal surgeon and co-author of the 2019 guidelines, told InSight+ there were many variables in the MJA research which made it difficult to compare to practices today.

“They are looking at data from 1999. The only people with the long term follow-up are the people (who have colonoscopies) without current equipment, current quality, current expertise. So, this data wouldn’t even have been used for the guidelines. It’s a different focus now,” Dr Barclay explained.

Dr Hamarneh agreed that it was difficult to compare.

“Everything is improving, and it may be difficult to compare a colonoscopy that was done in 1999 with a colonoscopy that is being done at this point and calling them equivalent. But, overall, the data still reflect their real-world practice, and this is what was found at that time point,” he said.

Dr Barclay said it was important to highlight that advanced neoplasia didn’t mean patients were definitely going to get colorectal cancer.

“If you’re just taking this on face value, what does it actually mean? It means that of all the people who have a colonoscopy, this proportion, the lowest risk of the lowest risk, a number of them might get something that over 5, 10 or 20 years might become a problem. We’re not saying that 30% of the whole population is going to get colorectal cancer,” Dr Barclay said.

What makes it more complicated was how diverse advanced neoplasia can be and how much colorectal cancer risks vary depending on the pathology.

“When we look at two patients, one patient who, for example, has three small tubular adenomas that are 3 or 4 mm in size, and then compare them with someone who has a 15 mm tubular adenoma with high grade dysplasia – they technically both have advanced adenoma, but that doesn’t really put them in the same risk profile,” Dr Hamarneh explained.

According to Dr Barclay, when deciding on follow-up colonoscopies, it’s not just about the pathology. Doctors also need to understand the person sitting in front of them and consider the patient’s risk profile more broadly.

“That could be a 60-year-old healthy white male with a metabolic syndrome. Or it could be a 75-year-old gentleman with multiple medical problems who is more at risk of colonoscopy than he is of having an advanced adenoma in 5 or 10 years’ time. When I’m thinking of it as a blank ‘everyone should have’, that doesn’t consider that each person at each time needs an individualised assessment for their best benefit,” Dr Barclay said.

Both doctors agreed there were other ways to manage risk in the interim years before a follow-up colonoscopy.

“It would be reasonable to restart the faecal occult blood testing at the 5-year mark, rather than waiting for 10 years without any interval testing,” Dr Hamarneh said.

“This will decrease the risk of any missed pathology or any interval advanced neoplasia that may otherwise be missed if we just use the 10-year mark with nothing in between.”

These discussions with patients should also be an opportunity to talk about prevention.

“You could say …‘These are the ways you minimise your risk of developing further adenomas or bowel cancer over time’. This is a long conversation, but that’s the important conversation to actually make change,” Dr Barclay said.

“Really, the guidelines are not just saying ‘do it at 10 years’. They’re actually saying to consider what you’ve found. Consider this person in the context of who they are in this environment right now and make a recommendation based on that. Not a blanket statement,” Dr Barclay concluded.

5 thoughts on “Surveillance colonoscopies: how often and who?

  1. Anonymous says:

    Given that FOB tests are relatively inexpensive, easily performed and free of iatrogenic downsides perhaps we should encourage greater use?

  2. Anonymous says:

    dr williams is correct that polyp followup should be based on a number of factors, however frequent ie 3 yearly or in some cases shorter duration follow , means patients who might actually need a scope are kept waiting longer. just as he suggests a vested interest is involved in saving money, so to at the other end are endoscopists scoping to pay the kids school fees. guidelines are just that, a guide to what is considered a safe practice.

  3. Aniello Iannuzzi says:

    It seems we have become too rigid with the rules. Guidelines should not be set in stone like strict rules.

    Of greater concerns to me presently, however, is the number of colonoscopies not being done on account of the pandemic. Who knows how many cancers are being missed or allowed to progress?!

    Also, the pandemic makes me wonder about another rule that warrants a review, namely the need to have a sedationist or anaesthetist present. Many endoscopists did very well, very safely for many years.

  4. Ratnakar Bhattacharyya says:

    Surveillance clonoscopy must necessarily by tailored to the needs for individual patients regardless of guidelines, no two patients and their circumstanes, genetics being the same. If the patient has a stong family history of large bowel cancer I will advise them yearly FOB and regular follow up even if aymptmatic and healthy. Regardless of guidelines if there is any clinical concern, patient needs to undergo full workup including colonoscopy. It does imply there will be some negative colonoscopy but it will provde a great deal of relief for the patient with prospect of prologed life. I can report one of my patient in her late 70s with treated hypertenson and past h/o wide local excision of anaplastic SCC in left thigh which I ecised previously being followed by onologist with no recurrence, reported being short of beath on exhertion with no bowel or abdominal symptoms or no famiy h/o colorectal cancer. Her blood pressure was normal and she did not look anaemic or in CCF clinically. Only abnormal finding was mild localised tenderness over right lower abdmen. Her routine blood and FOB test showed positive FOB and iron def, anaemia. She recovered fully after right curative hemicolectomy after a colonscopy confirmed caecal cancer. She remained well for over 10 years when I followed up her last.
    Treating physician and patient wil have to make the right decision complimenting each other being aware that mistake can happen causing heart ache.

  5. Randal Williams says:

    Suggestions of the suitability of ten year colonoscopic follow up for polyps ( vs 5 years or less) could only come from those with a vested interest in saving money or resources. Follow-up periods should be individualised on the basis of factors such as age and co-morbidities , the number, histopathological status and location of polyps , family history ( particularly of colon cancer and young age at diagnosis ) and any known genetic predispositions to polyps/cancer. In my practice, the polyp follow up period recommended was never more than 5 years , and was a lot less in higher risk cases.

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