Risk factors for advanced adenomas amongst small and diminutive colorectal polyps: a prospective monocenter study

Background: The management of colorectal polyps <10mm in diameter is controversial. Our aim was to evaluate the rate and risk factors for advanced adenomas and high grade neoplasia amongst small (6-9 mm) and diminutive (1-5mm) colorectal polyps.

Methods: Endoscopic and pathological reports of colonoscopies performed in our centre were collected prospectively. Advanced adenoma was defined by presence of a villous component and/or high grade dysplasia; high grade neoplasia by presence of high grade dysplasia and/or intramucosal carcinoma.

Results: 1468 patients were included (53.1% male, mean age 59.5±14 years); 414 polyps <10mm were detected, 9.9% advanced adenomas and 1.7% high grade neoplasia. Amongst small polyps, 25 (35.2%) were advanced adenomas, mainly due to villous features, and 3 (4.2%) were high grade neoplasia. Polyp size was associated with advanced adenomas (odds ratio=8.47).

Conclusion: The rate of advanced adenomas amongst small polyps was 35%, mainly due to the presence of villous features. Polyp size was identified as a risk factor of advanced adenoma amongst polyps <10mm. Given these results, we believe that polypectomy should be warranted for patients presenting with small polyps at computed tomography colonography.