In an interim analysis of the ongoing EPoS II trial, 10,799 patients who had high-risk adenomas removed were randomized to a first follow-up colonoscopy after three or five years. After five years, 0.77% of the five-year group had developed colorectal cancer, compared with 0.82% of the three-year group, with no clear difference in how advanced the cancers were. The five-year group needed nearly 4,200 fewer examinations. In the parallel EPoS III study of 1,861 patients with serrated polyps, about 1% developed colorectal cancer within five years, and none died from it.

The trial includes nearly 21,000 patients at 52 hospitals in eight European countries, including Norway, Sweden and Denmark. Denmark enrolled nearly 2,000 patients, and Karolinska Institutet coordinated the Swedish part. The trial is funded mainly by the Research Council of Norway.

The results suggest that we need to reassess when these patients should be called in for their next colonoscopy.

“More than 99 per cent of patients did not develop colorectal cancer within five years of the polyps being removed. The results suggest that we need to reassess when these patients should be called in for their next colonoscopy,” says Hans-Olov Adami, Professor Emeritus at Karolinska Institutet’s Department of Medical Epidemiology and Biostatistics.

Source: Karolinska Institutet, September 16, 2026 — read the release · Aarhus University — read the release · Read the study in NEJM