Five-year colonoscopy follow-up matched three-year for cancer risk in large European trial
Patients who had high-risk polyps removed and waited five years for their first follow-up colonoscopy had a colorectal cancer risk similar to those examined after three years, according to two studies in the New England Journal of Medicine involving Karolinska Institutet (KI) researchers.
In the EPoS II trial, 10,799 patients in eight European countries who had previously had high-risk adenomas removed were randomised to a first follow-up colonoscopy after three or five years. After five years of follow-up, 0.77% of the five-year group had developed cancer, compared with 0.82% of the three-year group, with no clear difference in cancer stage. The five-year group underwent nearly 4,200 fewer examinations. In the parallel EPoS III study of 1,861 patients with serrated polyps, about 1% developed colorectal cancer after five years and none died from it.
Hans-Olov Adami, Professor Emeritus at KI’s Department of Medical Epidemiology and Biostatistics, who coordinated the Swedish part of the project, said: “The results suggest that we need to reassess when these patients should be called in for their next colonoscopy.”
Published: September 22, 2026
