Outcomes of endoscopic mucosal resection for large superficial non-ampullary duodenal adenomas.

Endoscopic mucosal resection (EMR) is the recommended treatment for superficial non-ampullary duodenal epithelial tumors larger than 6 mm. This endoscopic technique carries a high risk of adverse events. Our aim was to identify the risk factors for adverse events following EMR for non-ampullary duodenal adenomatous lesions. We retrospectively analyzed a prospectively collected database of consecutive endoscopic resections for duodenal lesions at a tertiary referral center for therapeutic endoscopy. We analyzed patients with non-ampullary duodenal adenomatous lesions ≥ 10 mm resected by EMR, and searched for factors associated with adverse events after EMR. 167 duodenal adenomatous lesions, with a median size of 25 (25-40) mm, were resected by EMR between January 2015 and December 2020. Adverse events occurred in 37/167 (22.2%) after endoscopic resection, with 29/167 (17.4%) delayed bleeding, 4/167 (2.4%) immediate perforation and 4/167 (2.4%) delayed perforation. In logistic regression, the size of the lesion was the only associated risk factor of adverse events (OR = 2.81, 95% CI [1.27; 6.47], p = 0.012). Adverse events increased mean hospitalization time (7.7 ± 9 vs. 1.9 ± 1 days, p < 0.01). None of the currently recommended preventive methods, particularly clips, affected the adverse event rate. EMR of centimetric and supracentimetric duodenal adenomatous lesions carries a high risk of adverse events, increasing with the size of the lesion and with no benefit from any preventive method. These results suggest that these procedures should be performed in expert centers, and underline the need for novel endoscopic tools to limit the rate of adverse events.