Endoscopic features and clinical course of colorectal carcinoma resected by cold snare polypectomy

Background and aim: Cold snare polypectomy is commonly performed to remove small colorectal polyps. Accidental resection of carcinomas during this procedure has been reported. Herein, we aimed to clarify the clinicopathological features and clinical course of colorectal carcinomas resected by cold snare polypectomy.

Methods: This multicenter retrospective cohort study was conducted at 10 Japanese healthcare centers. Of the colorectal lesions resected by cold snare polypectomy between April 2016 and March 2020, lesions pathologically diagnosed as carcinoma were reviewed. Centralized histology (based on the Vienna classification) and endoscopic reviews were performed. The study endpoints were endoscopic features and clinical outcomes of cold snare polypectomy-resected colorectal carcinomas (Vienna category ≥4.2).

Results: We reviewed 74 of the 70 693 lesions resected by cold snare polypectomy. After a central pathological review, 68 lesions were diagnosed as carcinomas. The Japan Narrow-band imaging Expert Team (JNET) classification type 2B, lesion size ≥6 mm, and multinodular morphology were the significant endoscopic predictors of carcinoma resected by cold snare polypectomy. No adverse events related to the procedure occurred. Sixty-three lesions were diagnosed as carcinomas within the mucosal layer, and 34 were curative resections. Of the five carcinoma lesions with submucosal invasion, additional surgery revealed remnant cancer tissues in one lesion. No local or metastatic recurrence was observed during follow-up.

Conclusions: Although most of the carcinomas resected by cold snare polypectomy were within the mucosal layer, few lesions invading the submucosa were identified. Careful pre-procedural endoscopic evaluation, especially focusing on the JNET classification and multinodular morphology, is recommended.