Matsueda K, Kanesaka T, Kitamura M, et al. - This retrospective study was conducted to clarify long-term results of endoscopic resection for nonampullary duodenal neuroendocrine tumors. Participants were consecutive patients with nonampullary duodenal neuroendocrine tumors endoscopically managed between January 2005 and June 2020. There were 33 patients (97%), among 34 patients with 34 lesions, who had endoscopic mucosal resection, and one (3%) had endoscopic submucosal dissection. In 33 lesions (97%), en bloc resection was achieved. In 20 lesions (59%), R0 resection was achieved. A median follow-up of 47.9 months (range: 9.0–187.1) revealed no recurrence or metastasis development. The 5-year overall survival and recurrence-free survival rates were estimated to be 87.1% and 100%, respectively. Overall, a favorable long-term prognosis was shown to be conferred by endoscopic resection in patients with nonampullary duodenal neuroendocrine tumors without lymph node metastasis.