Efficacy and safety of cold-snare endoscopic mucosal resection for colorectal adenomas 10 to 14 mm in size: a prospective observational study

Background and Aims Cold-snare endoscopic mucosal resection (CS-EMR) has been adapted in a piecemeal fashion as a safe and effective procedure for resection of colorectal polyps ≥10 mm. However, few data are available on en bloc CS-EMR for adenomas of 10 to 14 mm. Thus, this study evaluated the efficacy and safety of CS-EMR for these colorectal adenomas. Methods In this single-arm, prospective, observational study, patients with at least 1 slightly elevated and sessile colorectal adenoma measuring 10 to 14 mm were recruited to undergo CS-EMR. The primary outcome was histological complete resection rate by CS-EMR, which was defined as en bloc resection, with a pathologically negative vertical margin and no neoplastic tissue obtained from 4 quadrants of the mucosal defect margin. Secondary outcomes were en bloc resection rate by CS-EMR, failure rate of CS-EMR, and the incidence of adverse events. Results A total of 80 polyps from 72 patients were included. CS-EMR failed in 11 lesions (13.7%), all of which were resected using a high-frequency electric current. The rates of en bloc resection and histologic complete resection by CS-EMR were 82.5% (66 of 80) and 63.8% (51 of 80), respectively. No bleeding occurred during the CS-EMR procedure, and there was no delayed bleeding or perforation at the site where CS-EMR was performed. Conclusions CS-EMR can be safely performed in an en bloc fashion for some colorectal adenomas measuring 10 to 14 mm. However, there is room for improvement regarding the resectability and evaluation of the vertical margin after CS-EMR. (Clinical trial registration number: UMI31248.)