[Underwater Endoscopic Mucosal Resection in Non-pedunculated Colorectal Lesions: A Prospective Series in a Tertiary Center in Peru].

Abstract

Introduction: Underwater endoscopic mucosal resection is an alternative technique to conventional endoscopic mucosal resection, with potential advantages in efficacy and safety. In Latin America, there are few reports on its application.

Objective: To evaluate the effectiveness, feasibility, and safety of underwater endoscopic mucosal resection for non-pedunculated colorectal lesions in a Latin American series.

Materials and methods: A prospective, observational study conducted between December 2023 and December 2024. Consecutive patients with non-pedunculated colorectal lesions ≥ 10 mm without endoscopic signs of deep submucosal invasion were included. Demographic data, lesion characteristics, technical success, resection type, histological findings, complications, and six-month recurrence were recorded.

Results: Sixty patients with 67 lesions were included. The mean lesions size was 16.7 mm. The most common location was the right colon (56.7%), and the predominant morphology was granular LST (59.7%). Technical success was 100%, and en bloc resection was achieved in 91% of cases (96.5% for lesions ≤ 20 mm). Histology showed: tubular adenomas (47.7%), tubular adenomas with high-grade dysplasia (16.4%), serrated adenomas without dysplasia (4.4%), serrated adenomas with low-grade dysplasia (16.4%), and intramucosal adenocarcinomas (5.9%). Intraprocedural bleeding occurred in 11.9% and delayed bleeding in 2.9%, with no perforations. A significant association was found between lesion size and resection type (p < 0.001). Piecemeal resection was more frequent in lesions > 20 mm (RR 12.88; 95% CI: 2.75 - 60.43). At six months, control colonoscopy was performed in 85.1% of cases, with no evidence of recurrence.

Conclusions: Underwater endoscopic mucosal resection proved to be effective, safe, and feasible, with high en bloc resection rates, and low rate of complications and absence of short-term recurrence.