The majority of polyps removed at colonoscopy are diminutive (≤ 5 mm) to small(6-10 mm) and there are few guidelines for the best way for these polyps to be removed. We aimed to assess the feasibility and effectiveness of cold snare polypectomy with injection(CSPI) for polyps ≤10 mm.

This study prospectively and randomly selected 300 patients with colorectal polyps (diameter ≤ 10 mm) found by colonoscopy in the gastroenterology department of 900 Hospital of the Joint Logistics Team from January 2018 to December 2018 for a control study, candidates were randomized (1∶1)to be treated with either cold snare polypectomy with injection(CSPI) or cold snare polypectomy(CSP). A small submucosal injection was administered prior to removal of the polyp using cold snare in the CSPI, whlie not in CSP.After polypectomy, an additional 2-3 forceps biopsies under narrow-band imaging (NBI) were performed at the base and margins of polypectomy sites to assess completeness of resection. Polypectomy timing, retrieval and complications were recorded at the time of the procedure.

Three hundred patients were recruited with mean lesion size of polyps 7.7 mm in CSPI group(n=150) and 6.7 mm in CSP group(n=150). The patients′ baseline characteristics and the location, size and shape of polyps removed were similar between the 2 groups.The complete resection rate (CRR) was respectively with CSPI and CSP 96.7% vs.76.6%, (P<0.001), there was significant difference between the two groups.Retrieval was completed for all polyps.Immediate bleeding during the procedure was more common in CSP has 9 cases , but no occurred in CSPI group (P<0.05), the difference was statistically significant, and there were no delayed bleeding or delayed perforation after polypectomy.

Cold snare polypectomy with injection is a safe and effective technique for polyps, with a high complete resection especially for 6-10 mm polyps reach to 98.9%, and low procedure-related adverse events, but the time taken for the procedure is greater than cold snare.