Safety of Endoscopic Mucosal Resection Using a Bipolar Snare for Superficial Nonampullary Duodenal Epithelial Tumors and the Predictive Factors of Piecemeal Resection

Introduction: Endoscopic mucosal resection for small superficial nonampullary duodenal epithelial tumors is a noninvasive treatment; however, perforations can occur. Bipolar snares can reduce the risk of perforation due to small tissue damage. Currently, only few studies have reported endoscopic mucosal resection for small superficial nonampullary duodenal epithelial tumors using a bipolar snare and the effect of preoperative findings. Objective: To investigate (1) resectability and adverse events of endoscopic mucosal resection using a bipolar snare for small superficial nonampullary duodenal epithelial tumors and (2) the predictions of piecemeal resection. Methods: Between 2007 and 2017, 89 patients with 107 lesions underwent endoscopic mucosal resection using a bipolar snare. Among them, 88 lesions of 77 patients were evaluated. The primary outcome was the incidence of en bloc resection and R0 resection and adverse events. Risk factors associated with piecemeal resection, including preoperative lesion findings, were also examined. Results: The incidence rates of en bloc and R0 resections were 85.2 and 48.9%, respectively. Neither intraoperative or delayed perforations nor procedure-related mortality was noted. The nonlifting sign after submucosal injection was associated with an increase in piecemeal resection (odds ratio: 20.3, 95% confidence interval: 2.53–162; p = 0.005). Conclusion: Endoscopic resection for small superficial nonampullary duodenal epithelial tumors can cause perforation; however, endoscopic mucosal resection using a bipolar snare can be a safe treatment option as it does not cause perforations. The nonlifting sign after submucosal injection is a predictive factor for piecemeal resection.