Safety of cold polypectomy for small colorectal neoplastic lesions: a prospective cohort study in Japan

Background Cold polypectomy has been widely accepted for removal of small colorectal polyps. However, no large-scale prospective study exists as for its safety in Japan. We investigated this issue in this single-center, prospective cohort study in a total of 1198 colorectal polyps resected with cold polypectomy. Patients and methods Four hundred and seventy-four patients who underwent cold polypectomy for colorectal neoplastic lesions less than 10-mm diameter between September 2014 and October 2016 were enrolled. Primary outcome was the incidence of delayed bleeding within 2 weeks after the procedure. Secondary outcomes were the rate of immediate bleeding, perforation, endoscopic en bloc resection, and advanced histology. Results Cold polypectomy was performed on 1198 polyps in the 474 patients. No delayed bleeding or colonic perforation was observed. Immediate bleeding during the procedure, requiring endoscopic hemostasis, occurred in 97 lesions (8.1%), and all of them were successfully managed endoscopically. The endoscopic en bloc resection rate was 97.2%. Twenty-eight lesions (2.3%) were histologically diagnosed as advanced neoplasia; among them, three lesions were well-differentiated adenocarcinomas, and in two of them, a negative margin was not histologically confirmed. Conclusions Cold polypectomy for small colorectal polyps is a safe technique without significant complication, but careful endoscopic diagnosis at cold polypectomy is necessary to identify advanced neoplasia. The reliability of cold polypectomy in excision of polyps with high-grade neoplasia should be established before the procedure becomes standard in the excision of small colorectal polyps. Clinical trial registration number: UMIN000014812.