Hot snare polypectomy endoscopic mucosal resection using bipolar snare for intermediate size colorectal lesions: Propensity score matching.

Background: Endoscopic resection (ER) with bipolar snare, in which the electric current only passes through the tissue between the device's two electrodes, is a prominent method used to prevent perforation due to electricity potentially. ER using bipolar snare with or without submucosal injection enabled safe resection of colorectal lesions measuring 10-15 mm in an porcine model. ER with bipolar snare is expected to have good treatment outcomes in 10-15 mm colorectal lesions, with high safety even without submucosal injection. However, no clinical reports have compared treatment outcomes with and without submucosal injection.

Aim: To compare the treatment outcomes of bipolar polypectomy with hot snare polypectomy (HSP) to those with endoscopic mucosal resection (EMR).

Methods: In this single-centre retrospective study, we enrolled 10-15 mm nonpedunculated colorectal lesions (565 Lesions in 463 patients) diagnosed as type 2A based on the Japan Narrow-band Imaging Expert Team classification, resected by either HSP or EMR between January 2018 and June 2021 at the National Cancer Center Hospital East. Lesions were divided into HSP and EMR groups, and propensity score matching was performed. In the matched cohort, and R0 resection rates and adverse events were compared between the two groups.

Results: Of the 565 lesions in 463 patients, 117 lesions each in the HSP and EMR groups were selected after propensity score matching. In the original cohort, there was a significant difference in antithrombotic drug use ( < 0.05), lesion size ( < 0.01), location ( < 0.01), and macroscopic type ( < 0.05) between the HSP and EMR groups. In the matched cohort, the resection rates were comparable between both groups [93.2% (109/117) 92.3% (108/117), = 0.81], and there was no significant difference in the R0 resection rate [77.8% (91/117) 80.3% (94/117), = 0.64]. The incidence of delayed bleeding was similar in both groups [1.7% (2/117)]. Perforation occurred in the EMR group [0.9% (1/117)] but not in the HSP group.

Conclusion: Using bipolar snare, ER of nonpedunculated 10-15 mm colorectal lesions may be performed safely and effectively, even without submucosal injection.