Colonoscopy surveillance: five years holds up against three

Design

Randomised non-inferiority trial, interim analysis at 5.5 years

Population

10,799 patients after removal of high-risk adenomas

Primary outcome

Cumulative colorectal cancer incidence

Effect

0.77% (5-year) vs 0.82% (3-year); difference -0.05 percentage points, met non-inferiority

Guidelines currently recommend a first surveillance colonoscopy three years after removal of high-risk adenomas. The EPoS II trial randomised 10,799 such patients across eight European countries to a first surveillance colonoscopy at five years or at three, and this interim analysis reports colorectal cancer incidence after 5.5 years.

Less-frequent surveillance was non-inferior. The five-year cumulative incidence of colorectal cancer was 0.77% with the five-year strategy and 0.82% with the three-year strategy, a difference of -0.05 percentage points, with the upper confidence boundary inside the pre-set non-inferiority margin. Cancer stage at diagnosis and the handful of cancer deaths did not differ meaningfully.

This supports lengthening the first surveillance interval to five years after high-risk adenoma removal, which would ease colonoscopy demand. It is an interim read of a trial whose definitive endpoint is cancer incidence at ten years, so it is a reason to move, not yet to close the question.

• Randomised 10,799 patients after removal of high-risk adenomas to five-year or three-year first surveillance.
• Five-year colorectal cancer incidence was 0.77% versus 0.82%, a difference of -0.05 percentage points.
• The result met the pre-specified non-inferiority margin.
• Cancer stage at diagnosis did not differ meaningfully between groups.
• Lengthening the interval would ease colonoscopy capacity pressures.

Why it matters

Three-year surveillance may be more frequent than necessary, and the data give a basis to extend it.

Don't overread it

This is an interim analysis at 5.5 years; the definitive ten-year colorectal cancer outcome has not yet been reported.

The statistics, in plain English

Non-inferiority here means the five-year strategy was not meaningfully worse within a pre-set 0.7 percentage-point margin, not that it was better. The tiny absolute difference (-0.05 percentage points) and overlapping cancer deaths support that reading.

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