Waiting 5 years for the first colonoscopy after high-risk adenomas was as safe as 3 years

Design

Randomised non-inferiority trial (EPoS II), interim analysis, 8 European countries

Population

10,799 patients after removal of high-risk adenomas

Primary outcome

Cumulative colorectal cancer incidence (10-year primary; 5-year interim)

Effect

0.77% (5-year) vs 0.82% (3-year); difference −0.05 pp, upper 99.12% CI 0.68 (margin 0.7)

EPoS II randomised 10,799 patients in eight European countries who had high-risk adenomas removed (at least one 10 mm or larger, high-grade dysplasia or villous features, or 3 to 10 adenomas) to a first surveillance colonoscopy at 5 years or the currently recommended 3 years. The 3-year group was also scoped at 5 years.

At this interim analysis after 5.5 years, cumulative colorectal cancer incidence was 0.77% in the 5-year group and 0.82% in the 3-year group (difference −0.05 percentage points; upper boundary of the 99.12% CI 0.68, within the 0.7-point non-inferiority margin). Stage at diagnosis was similar. Five patients died of colorectal cancer: three and two respectively.

The final 10-year analysis is still to come. But the interim result supports a longer first interval, which would free colonoscopy capacity for diagnostic and screening work where access is limited, including in India.

• After removal of high-risk adenomas, a first surveillance colonoscopy at 5 years was non-inferior to 3 years at 5.5 years of follow-up.
• Complete, high-quality index colonoscopy with full polyp removal is the prerequisite.
• Patients with more than 10 adenomas, large piecemeal resections or hereditary syndromes were not part of this comparison.
• Guidelines have not yet changed; follow local guidance until they do.

Why it matters

It could free a large share of surveillance colonoscopies for patients who need them more.

Don't overread it

This is an interim analysis at 5.5 years of a 10-year trial.

The statistics, in plain English

Non-inferiority means the 5-year interval was not worse by more than 0.7 percentage points. The observed difference was essentially zero. Because this is an interim look, a very stringent 99.12% confidence interval was used.

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