Underwater EMR versus conventional EMR for superficial non-ampullary duodenal epithelial tumors in the Western setting

Background and aims Conventional endoscopic mucosal resection (C-EMR) is established as the primary treatment modality for superficial non-ampullary duodenal epithelial tumors (SNADETs) but recently underwater EMR (U-EMR) emerged as a potential alternative. The majority of previous studies focused on Asian populations and small lesions (≤20 mm). We aimed to compare the efficacy and outcomes of U-EMR versus C-EMR for SNADETs in a Western setting. Methods This was a retrospective multinational study from 10 European centers that performed both C-EMR and U-EMR between January 2013 and July 2023. The main outcomes were the technical success, procedure-related adverse events (AEs), and the residual/recurrent adenoma (RRA) rate, evaluated on a per-lesion basis. We assessed the association between the type of EMR and the occurrence of AEs or RRA using mixed-effects logistic regression models (propensity scores). Sensitivity analyses were performed for lesions ≤ or >20 mm. Results A total of 290 SNADETs submitted to endoscopic resection during the study period met the inclusion criteria and were analyzed (C-EMR n=201, 69.3%; U-EMR n=89, 30.7%). Overall technical success rate was 95.5% and comparable between groups. In logistic regression models, compared with U-EMR, C-EMR was associated with a significantly higher frequency of overall delayed AEs (OR 4.95; 95%CI=2.87-8.53), post-procedural bleeding (OR=7.92; 95%CI=3.95-15.89) and RRA (OR=3.66; 95%CI=2.49-5.37). Sensitivity analyses confirmed these results when solely considering either small (≤20 mm) or large (>20 mm) lesions. Conclusion Compared with C-EMR, U-EMR was associated with a lower rate of overall AEs and RRA, regardless of lesion size. Our results confirm the possible role of U-EMR as an effective and safe technique in the management of SNADETs.