Endoscopic Diagnosis and Treatment for Superficial Non-Ampullary Duodenal Epithelial Tumors

The widespread use of high-resolution and screening endoscopy has led to the increased detection of superficial non-ampullary duodenal epithelial tumors (SNADETs) in routine clinical practice. According to a national cancer registry analysis in Japan, many SNADETs are identified at an early localized stage, making endoscopic diagnosis and treatment the primary management strategies. However, endoscopic treatment of duodenal lesions remains technically demanding because of the thin muscular layer, rich vascularity, and continuous exposure to bile and pancreatic juice, which increases the risk of delayed bleeding and perforation. Moreover, forceps biopsy has limited diagnostic accuracy and may induce fibrosis, compromising subsequent endoscopic resection. This review summarizes the practical approaches to endoscopic management of SNADETs, focusing on pretreatment assessment, treatment selection, and adverse event prevention. Pretreatment diagnosis has shifted toward optical evaluation using white-light imaging and magnifying image-enhanced endoscopy, which allow accurate estimation of histology and invasion depth while avoiding biopsy-related disadvantages. Treatment strategies should be determined based on the lesion size, mucin phenotype, location, suspected malignancy, feasibility of defect closure, and institutional expertise. Herein, the advantages and limitations of the currently available techniques, including cold snare polypectomy, endoscopic mucosal resection, underwater endoscopic mucosal resection, endoscopic submucosal dissection, and laparoscopic-endoscopic cooperative surgery, are discussed. An integrated strategy combining accurate optical diagnosis, appropriate therapeutic selection, and risk reduction is essential for safe and effective endoscopic treatment of SNADETs.