CRC Surveillance may be Unnecessary After Polypectomy in Some Patients

Carol A. Burke, MD, FACG, FASGE, AGAF, FACP

This important study from the UK looks at the impact of polypectomy on future risk of colorectal cancer and the impact of follow up surveillance on that risk. It adds evidence to support the stratification of patients with adenomatous polyps into lower and higher risk groups for future CRC based upon their baseline polyp characteristics. We’ve been stratifying patients into low and high-risk groups in the United States for decades. Europeans stratify their patients into three slightly different groups: low, intermediate and high.

The study is retrospective, with its inherent limitations, but demonstrates low-risk patients (with 1-2 adenomas, < 10 mm in size, without any villous features, or proximal polyps) can have a de-escalation in colonoscopy use after baseline polyp removal. The incidence of CRC after polypectomy and without follow up surveillance was 50% lower than the general population incidence. These data suggest these individuals are safe to return to average risk colorectal screening which in Europe, is with the use of fecal immunochemical testing. In intermediate-risk patients (those with 3-4 adenomas, < 10 mm in size or 1-2 adenomas with one or more at least 10 mm in size , who have undergone complete colonoscopy, with adequate bowel preparation, and no proximal polyps or an adenoma with high grade dysplasia, or adenoma greater than 20 mm  in size) had the same risk for CRC as the general population without repeat colonoscopy and lower than the general population risk with one surveillance colonoscopy. The subset of those patients with unknown or incomplete colonoscopy, inadequate bowel preparation, proximal polyps or adenomas with high grade dysplasia or at least 20 mm in size, had a higher than population risk for CRC without surveillance but decreased to population risk after one surveillance exam.

High risk patients (with five or more adenomas or three or more adenomas including one of at least 10 mm in size, with incomplete exams or completeness unknown, or adenomas with high grade dysplasia) stayed at a higher than population risk for CRC until after a second surveillance exam. This supports that the high-risk population requires ongoing surveillance, while the intermediate risk group benefits from one post polypectomy surveillance exam.

The study is reassuring, and supports emerging data showing the very low risk for CRC in the lowest risk patients. It expands our knowledge of a lower than previously thought risk in individuals with 3-4 small adenomas. This data supports the new post-polypectomy guidelines by the US Multi-Society Task Force recommendations lengthening the interval in patients with 1-2 small tubular adenomas to 7-10 years, and to 3-5 years in individuals with 3-4 small, tubular adenomas.  Accumulating more data is important so we can be prudent and judicious in our use of colonoscopy resources, saving the exam for those most likely to benefit: individuals who have never been screened, those who have high-risk polyp features, and those with a familial or genetic cause of CRC.