Introduction: Underwater endoscopic mucosal resection (uEMR) technique has gained popularity for removal of large non-pedunculated colorectal polyps (LNPCPs) due to high en-bloc resection rates and lower recurrence rates. However, there is no information regarding outcomes of uEMR for giant colorectal polyps. Therefore, we aimed to evaluate the outcomes of uEMR for giant colorectal polyps across multiple centers in North America. Methods: We conducted a multicenter retrospective study of adults with giant colorectal polyps undergoing uEMR between Jan 2019-Nov 2025. Giant colorectal polyps were defined as LNPCPs ≥40 mm. Primary outcomes were technical success and rate of recurrent adenoma. Secondary outcomes were severe adverse events (SAEs) and predictors of technical success, recurrence and SAEs. Results: A total of 137 polyps, with mean polyp size 47.6 mm were included. Majority of the lesions were located in right colon (61%,n=83) with the most common histopathology being high-grade dysplasia (HGD) (31.4%, n=43). Technical success was achieved in 90.5% (n=124) with en-bloc resection rate of 11.7% (n=16). Polyp fibrosis (OR: 0.08) and HGD (OR: 0.15) were independent predictors of inability to achieve technical success. Of 92 (67.1%) patients with follow up, recurrent polyp was present in 8.7% (n=8). SAEs was noted in 9.5%, consisting of delayed bleeding (9.5%, n=13), while no delayed perforation or post polypectomy syndrome was noted. Discussion: Our study demonstrates that uEMR is technically feasible for removal of giant colorectal polyps with an acceptable safety profile and recurrence rate.
Karna et al. (Wed,) studied this question.