Effectiveness and safety of the different endoscopic resection methods for 10-to 20-mm nonpedunculated colorectal polyps: A systematic review and pooled analysis

Background: We performed a systematic review and pooled analysis to assess the effectiveness and safety of different endoscopic resection methods for 10- to 20-mm nonpedunculated colorectal polyps. Methods: Articles in PubMed, EMBASE, and the Cochrane Library related to the common endoscopic treatment of 10- to 20-mm nonpedunculated polyps published as of April 2020 were searched. Primary outcomes were the R0 resection rate and en bloc resection rate. Secondary outcomes were safety and the recurrence rate. Meta-regression and subgroup analysis were also performed. Results: A total of 36 studies involving 3212 polyps were included in the final analysis. Overall, the effectiveness of resection methods with a submucosal uplifting effect, including endoscopic mucosal resection (EMR), cold EMR and underwater EMR (UEMR), was better than that of methods without a nonsubmucosal uplifting effect [R0 resection rate, 90% (95% confidence interval (CI) 0.81-0.94, I-2 = 84%) vs 82% (95% CI 0.78-0.85, I-2 = 0%); en bloc resection rate 85% (95% CI 0.79-0.91, I-2 = 83%) vs 74% (95% CI 0.47-0.94, I-2 = 94%)]. Regarding safety, the pooled data showed that hot resection [hot snare polypectomy, UEMR and EMR] had a higher risk of intraprocedural bleeding than cold resection [3% (95% CI 0.01-0.05, I-2 = 68%) vs 0% (95% CI 0-0.01, I-2 = 0%)], while the incidences of delayed bleeding, perforation and post-polypectomy syndrome were all low. Conclusions: Methods with submucosal uplifting effects are more effective than those without for resecting 10- to 20-mm nonpedunculated colorectal polyps, and cold EMR is associated with a lower risk of intraprocedural bleeding than other methods. Additional research is needed to verify the advantages of these methods, especially cold EMR.