A single center retrospective analysis of feasibility of diagnostic endoscopic resection for grade 1 or 2 gastric neuroendocrine tumors

Currently, endoscopic resection is recommended for gastric neuroendocrine tumors (G-NETs) < 10 mm. However, a larger G-NETs can also be resected endoscopically. Here, we evaluated the feasibility of diagnostic endoscopic resection of G-NETs. We retrospectively analyzed 31 patients, diagnosed with grade 1 or 2 G-NETs at a single tertiary referral center, between January 2009 and December 2023. Outcomes analyzed included histopathology, complete resection, and metastasis rates. The mean follow-up period was 38.9 ± 38.4 months; mean size of G-NETs was 4.9 ± 3.4 mm, and the most size of G-NETs were < 10 mm (87.1%). The maximal NET diameter was 16 mm. Most NETs were grade 1 (type 1: 90.9%; type 3: 85.0%). None of the enrolled patients showed evidence of lymph node metastasis or local recurrence. Even in R1 resection (19.4%) showed no metastasis during follow-up without additional surgery. Recurrent or multiple G-NETs were observed only in patients with type 1 NETs (27.2%, 3/11). Modified endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) showed a 100% complete resection rate. After resection, grade 1 or 2 G-NETs had no lymph nodes or distant metastases during the follow-up period. This study suggests that G-NETs smaller than 16 mm can be considered for diagnostic endoscopic resection and this resection may be potentially definitive treatment.