Abstract / Summary
Background: Although non-ampullary duodenal epithelial tumors (NADETs) were historically considered rare, their detection has increased with high-resolution and image-enhanced endoscopy. Endoscopic resection is the preferred organ-preserving treatment for lesions without evidence of nodal metastatic risk, but the thin, vascular duodenal wall and exposure to bile and pancreatic juice create a narrow safety margin. Methods: This structured narrative review searched PubMed/MEDLINE, Embase, Web of Science Core Collection, and the Cochrane Library through 4 August 2026 and synthesized current guidance and clinical evidence. Results: Pooled conventional endoscopic mucosal resection (CEMR) data showed 93% successful removal and 15% recurrence, whereas contemporary endoscopic submucosal dissection (ESD) data showed 98.1% en bloc resection with 8.5% intraprocedural perforation. Cold snare resection is best supported for diminutive nonmalignant lesions; CEMR or underwater EMR is appropriate for most snareable lesions ≤ 20 mm; and hot EMR remains suitable for many larger lesions without invasive features. ESD should be reserved for lesions requiring en bloc histology in expert centers; nonlifting, fibrotic, large, or closure-challenging lesions may require endoscopic full-thickness resection, laparoscopic-endoscopic cooperative surgery, or surgery. Suspected deep invasion or nodal disease requires multidisciplinary evaluation. Conclusions: Treatment should be individualized according to lesion size, morphology, invasion depth, papillary relation-ship, closure feasibility, patient fitness, and local expertise. Suspected deep invasion or nodal disease requires multidisciplinary evaluation. Complete defect closure is central to safety, and sporadic and familial adenomatous polyposis-associated disease require separate assessment.