PurposeThis study aimed to assess the safety and efficacy of endoscopic submucosal dissection (ESD) and pre-cutting endoscopic mucosal resection (pEMR) in treating non-ampullary duodenal subepithelial lesions (NADSELs) and to evaluate the clinical utility of endoscopic ultrasound (EUS) before endoscopic resection (ER).MethodsIn this retrospective single-centre cohort study, we compared the clinical outcomes of patients with NADSELs who underwent ESD or pEMR between January 2014 and June 2023. The accuracies of EUS in determining the pathological type and origin of the lesions were evaluated using postoperative histopathology as the gold standard.ResultsOverall, 56 patients with NADSELs underwent ER in this study, including 16 and 40 treated with pEMR and ESD, respectively. There were no significant differences between the two groups in terms of en bloc resection rate, complete (R0) resection rate, perioperative complication rate, and postoperative hospital length of stay (P > 0.05). However, the pEMR group had significantly shorter median operational (13.0 min vs. 30.5 min, P < 0.001) and mean fasting (1.9 days vs. 2.8 days, P = 0.006) time and lower median hospital costs (¥12,388 vs. ¥19,579, P = 0.002). The accuracies of EUS in determining the pathological type and origin of the lesions were 76.8% and 94.6%, respectively, compared with histopathological evaluation.ConclusionsEUS can accurately predict the origin of NADSELs. Suitable lesions determined to originate from the submucosa or more superficial layers using EUS can be treated using pEMR as it shortens the operational and recovery time, reduces hospitalisation costs, and achieves an R0 resection rate similar to ESD.