Long-term effects of colonoscopy screening on colorectal cancer incidence and mortality: a multicountry, population-based randomised controlled trial
A large international trial shows one colonoscopy screening reduces colorectal cancer occurrence by nearly half, offering substantial protection from this common disease.
This 13-year multicountry RCT (n=84,583) found that a single colonoscopy reduced colorectal cancer incidence by 19% in the intention-to-screen analysis and 45% per-protocol, but did not demonstrate a statistically significant mortality benefit, partly because CRC mortality in controls was lower than expected at trial design. The findings directly inform ongoing global debates about optimal CRC screening strategy and the magnitude of colonoscopy's protective effect.
What the study was
- Study design
- Multicountry population-based RCT (intention-to-screen and per-protocol analyses), 13-year follow-up
- Population
- Men and women aged 55-64 years; Norway, Poland, Sweden
- Sample size
- 84583
- Category
- Early Detection
- Maturity
- Potentially Practice-Changing
- Journal
- Lancet
Why it surfaced
Landmark Lancet RCT with 13-year follow-up, n=84,583, direct practice implications for CRC screening guidelines globally. Per-protocol results (RR 0.55 incidence, 0.70 mortality) will be heavily cited; intention-to-screen non-significant mortality result generates important clinical debate.
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