“Nonadvanced” Adenomas Are Not One Risk Category: Gastroenterology | October 2026

What Did the Study Find?

Investigators studied 16,870 adults aged 50–75 years who underwent at least two colonoscopies between 2004 and 2023. During a median 5.3 years, five-year advanced colorectal neoplasia incidence rose stepwise from 1.3% with no adenoma to 4.0% with 1–2, 5.3% with 3–4, and 10.1% with 5–10 nonadvanced adenomas. Corresponding adjusted hazard ratios versus no adenoma were 1.64, 2.75 and 5.21.

Size added clinically important discrimination within the same numerical category. Among patients with 1–2 adenomas, five-year risk was 5.5% when at least one measured 6–9 mm, versus 3.7% when all were ≤5 mm. For 3–4 adenomas, risk was 8.1% versus 3.0%, respectively. The study was observational, conducted in a Korean health-screening population, and cannot determine whether shortening surveillance improves outcomes. ScienceDirect

Why Does It Matter?

Surveillance algorithms commonly emphasise adenoma count while grouping every lesion below 10 mm together. These results suggest that a patient with several 6–9-mm adenomas may carry materially greater risk than one with the same number of diminutive lesions.

GastroAGI Takeaway

Record subcentimetre adenoma size accurately: “6–9 mm” and “≤5 mm” should not automatically imply the same surveillance risk.