Long-term outcomes of endoscopic resection for well-differentiated nonampullary duodenal neuroendocrine tumors

Nonampullary duodenal neuroendocrine tumors (NAD-NETs) are rare with limited evidence regarding endoscopic treatment. The study aimed to investigate the efficacy and safety of endoscopic resection of well-differentiated NAD-NETs and evaluate long-term outcomes, including local recurrence and metastasis.A total of 78 patients with NAD-NETs who underwent endoscopic resection between January 2011 and August 2022 were included. The clinicopathologic characteristics and treatment outcomes were collected and analyzed.En bloc resection was achieved for 74 of the tumors (94.9%) and R0 resection was obtained in 68 of the tumors (87.2%). Univariate analysis identified tumors in the second part of the duodenum, tumor size ≥ 10 mm and muscularis propria invasion as risk factors for non-curative resection. Two patients with R1 resection (vertical margin involvement) and two patients with lymphovascular invasion underwent additional surgery. Four patients experienced adverse events (5.1%), including two cases of delayed bleeding and two cases of perforation, all successfully managed conservatively. During a median follow-up period of 62.6 months, recurrence and lymph node metastasis were only detected in one patient with R1 resection 3 months after the original procedure.Endoscopic resection is safe and effective and provides a favorable long-term outcome for patients with well-differentiated NAD-NETs without regional lymph node or distant metastasis.