Follow-up tests after an initial colonoscopy may reduce the number of people diagnosed with bowel cancer, according to a new study.
The findings suggest that patients at intermediate risk of developing bowel cancer who had at least one follow-up colonoscopy after screening were less likely to develop the disease. And there may be some patients at low risk who weren’t benefiting from follow-up colonoscopy.
These patients at low risk could be followed-up in a different way, to avoid unnecessary testing.
The study, funded by the National Institute for Health Research, is published in The Lancet Oncology.
Clare Hyde, Cancer Research UK’s health information officer, said that the study helps shed light on who is most likely to benefit from colonoscopy.
In England, Wales and Northern Ireland people aged between 60 and 74 are invited to take part in bowel screening using a home testing kit. In Scotland screening is offered to people aged between 50 and 74.
The testing kit looks for miniscule traces of blood in poo samples. If the result shows blood in the sample, the person will have a colonoscopy.
A colonoscopy looks for signs of bowel cancer and small growths in the bowel, called polyps or adenomas, which can develop into cancer.
Removing these growths can reduce the risk of developing bowel cancer, and some patients will then be recommended to have follow-up colonoscopies every 3 years.
The study looked back at records for 12,000 patients from 17 UK hospitals over an average of nearly 8 years. The patients were classed as being at medium risk of developing bowel cancer based on the number and types of polyps detected at a first colonoscopy.
Just under 6 in 10 of those patients attended at least one follow-up appointment. The incidence of bowel cancer in these patients was then compared with those who didn’t attend a follow-up colonoscopy.
Patients within the intermediate risk group who had larger, more aggressive looking polyps, or polyps in the upper half of the large bowel, were found to be more at risk of developing bowel cancer.
These patients were the most likely to benefit from at least one follow-up colonoscopy. And the greatest impact on reduction in bowel cancer incidence appeared to be due to the first appointment.
According to the study, while most patients in the medium risk group were shown to benefit, those towards the lower risk end of this group possibly don’t require additional colonoscopy. Up to a third of people who were having these test potentially didn’t need them.
“Colonoscopies carry a small risk of complications for patients, and are demanding on NHS resources, with around 1 in 5 colonoscopies in the UK performed for surveillance,” said Professor Wendy Atkin, study lead from Imperial College London.
“It is therefore important to assess whether all people classed as being at intermediate risk need to undergo follow-up colonoscopy.”
Hyde agreed that steps are needed to work out the best follow-up tests for individual patients, ensuring they don’t have unnecessary tests, and reducing the pressure on hospital resources.
“Since less than 60 per cent of people attended their first follow-up, it will be important to look at how we can make sure that more people are encouraged and able to attend their appointments,” she added.
A limitation of this kind of study is that it looks back at existing information and so can’t definitively prove a link between surveillance and incidence of bowel cancer.
Atkin, W., et al. (2017) Adenoma surveillance and colorectal cancer incidence: a retrospective, multicentre, cohort study. The Lancet Oncology. DOI: 10.1016/S1470-2045(17)30187-0