ColonCancerCheck’s surveillance recommendations are evidence based. They are designed to ensure the benefits of surveillance colonoscopies outweigh their potential harms. ColonCancerCheck now considers that people with 1 or 2 low risk adenomas are at average or lower-than-average risk. Therefore, surveillance colonoscopy is no longer recommended for these people. Instead, they should return to average risk screening with the fecal immunochemical test (FIT) 5 years after their initial colonoscopy.
These recommendations were developed after ColonCancerCheck conducted a systematic review and meta-analysis examining literature published between January 2006 and July 2015 on the risk of developing high risk adenomas, developing colorectal cancer or dying from colorectal cancer after the removal of low risk adenomas. The review found that people who had low risk adenomas during their initial colonoscopy were at lower risk of developing colorectal cancer and dying from colorectal cancer when compared with the general population.
However, the review also found that, when compared with people with a normal prior colonoscopy, people with prior low risk adenomas have a small but statistically significant increased risk of developing high risk adenomas. Based on the literature available at the time, it was not possible to determine if this statistically significant increased risk of developing high risk adenomas translates to an increased risk of developing colorectal cancer or dying from the disease when compared with people with a prior normal colonoscopy.
Due to this lack of clarity, ColonCancerCheck took a conservative approach and advised that people with low risk adenomas found during their initial colonoscopy return to average risk screening with FIT earlier than people with normal colonoscopy findings (i.e., in 5 years instead of 10 years).
Since then, numerous cohort studies with long-term follow-up found that the risk of developing colorectal cancer and the risk of dying from colorectal cancer is similar between people with prior low risk adenomas and no adenomas at colonoscopy.
In addition, several recent studies have also strengthened the evidence that people with low risk adenomas have a lower risk of developing colorectal cancer and dying from colorectal cancer when compared with the general population.
This emerging body of evidence supports ColonCancerCheck’s recommendation to not perform colonoscopy surveillance in people with prior low risk adenomas, but to instead screen these individuals with FIT.