Which lesions are at higher risk of developing colorectal carcinomas: superficially elevated serrated lesions or depressed lesions?

Abstract

Background: There are lesions that are still being missed in colonoscopy. Many of those could be superficially elevated serrated lesions or depressed ones. Aim: Compare the histopathological characteristics of these lesions and their risks for submucosal carcinoma. Methods: Retrospective, cross-sectional and observational study comparing 217 superficially elevated serrated lesions larger than 5 mm resected by colonoscopies (G1) with 558 depressed lesions (G2). Results: In G1, 217 lesions were found in 12653 colonoscopies (1,7%); in G2, 558 lesions in 36174 colonoscopies (1.5%). In G1 there were 63.4% of women and in G2 no gender predominance. Average size was G1 with 16.2 mm and G2 with 9.2 mm (p<0.001). G1 predominated on the proximal colon and G2 on the distal and rectum (p<0.001). In G1 there were 214 low-grade intramucosal neoplasia (98,6%) and three high grade intramucosal neoplasia (1,4%). Excluding 126 hyperplastic polyps and considering 91 sessile serrated adenomas in G1, was observed 88 (96.7%) with low-grade intramucosal neoplasia and three (3.3%) high-grade intramucosal neoplasia; in G2, 417 low-grade intramucosal neoplasia (74,7%), 113 high-grade intramucosal neoplasia (20,3%) and 28 (5,0%) submucosal adenocarcinomas (p<0.001). Conclusion: Depressed lesions significantly had more high-grade intramucosal neoplasia and more invasive carcinomas for the submucosal layer than superficially elevated serrated lesions and more than superficially elevated sessile serrated adenomas.