Efficacy and safety of underwater endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumors: a systematic review and meta-analysis.

Background Superficial non-ampullary duodenal epithelial tumors (SNADET) are increasingly found during upper endoscopy. Underwater endoscopic mucosal resection (UEMR) is an emerging technique for the endoscopic resection of SNADET. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of this technique. Methods We conducted a comprehensive search of several databases from inception to August 2019, which included Ovid Cochrane Database of Systematic Reviews, Ovid Embase, Scopus, Ovid Cochrane Central Register of Controlled trials, Ovid MEDLINE®, and In-Process and other non-indexed citations. The primary outcome assessed was the pooled clinical success rate of UEMR. Secondary outcomes included rate of en bloc resection, pooled rate of high-grade dysplasia or intramucosal carcinoma (HGIC), and pooled rate of adverse events. Meta-regression analysis was performed based on tumor size. Results A total of 8 study arms were included for analysis with UEMR performed in a total of 258 lesions. The pooled clinical success rate was 89.9% (95% confidence interval [CI] 83.4-94.1). En-bloc removal was achieved in 84.6% of treated lesions (95%CI 75.5-90.7). The pooled rate of HGIC was 24.7% (95%CI 10.3-48.3). The pooled rate of adverse events was 6.9% (95%CI 2.5-17.9). This included 10 total adverse events, with the majority being self-limited delayed bleeding. There were no duodenal perforations. Conclusions UEMR for endoscopic resection of SNADET has a high efficacy. In addition, this technique has a high rate of en bloc resection and an acceptable adverse event profile. Given these data, UEMR should be considered as a method for endoscopic resection of SNADET.