Surveillance colonoscopy after removal of high-risk polyps is a cornerstone of colorectal cancer prevention, but it is invasive, resource-intensive and unpleasant for patients. Researchers from Karolinska Institutet took part in two studies published in the New England Journal of Medicine indicating that the interval between examinations can likely be extended from the current three years to five without increasing cancer risk.
The headline evidence comes from the EPoS II randomised trial, reported as Colonoscopy Intervals and Colorectal Cancer Incidence after Adenoma Removal. It compared first surveillance at three versus five years in patients whose removed adenomas met high-risk criteria: lesions of 10 millimetres or larger, high-grade dysplasia or villous growth, or three to ten adenomas. In the interim analysis, five-year surveillance was non-inferior to three-year surveillance for colorectal cancer incidence during the first five years, with more than 99 per cent of patients in both arms remaining free of a cancer diagnosis.
The companion paper in the same journal addressed colorectal cancer risk associated with serrated polyps, rounding out the evidence base on which surveillance policy rests. Karolinska Institutet noted that adopting longer intervals could reduce the number of examinations, sparing patients repeated invasive procedures and releasing substantial endoscopy capacity, a meaningful efficiency gain for health systems facing steadily growing demand for both screening and surveillance.