Management Strategies and Outcomes for Type 1 Gastric Neuroendocrine Tumors Measuring More Than 1 cm.

Objectives. Type 1 gastric neuroendocrine tumors (T1g-NETs) are well-differentiated lesions with excellent survival but frequent recurrence. Tumor size is the main prognostic factor, yet optimal management for tumors >1cm remains uncertain. This study aimed to evaluate treatment strategies and outcomes in patients with T1g-NETs>1 cm. Methods. We conducted a retrospective multicenter study including 106 adults with T1g-NETs>1 cm. Clinicopathologic and management data were collected. The primary outcome event was a composite unfavorable outcome (UO), defined as recurrence or progression, used to analyze progression-free survival as the main time-to-event outcome. Analyses included multinomial logistic regression, Cox models, and Kaplan–Meier curves (p<0.05). Results. Among 106 patients (58.5% female; median age 59), median tumor size was 15mm. Most tumors were Grade 1 (61.4%) or Grade 2 (37.7%), with median Ki-67 of 2%. Endoscopic resection was performed in 76 patients (71.7%), surgery in 33 (31.1%, including 13 initially treated endoscopically), and 10 (9.4%) were surveilled. Over a median 61-month follow-up, 24 patients (22.6%) recurred, 8 (7.5%) progressed; only 2 deaths (1.9%) were tumor-related. Larger tumors were associated with UO (p=0.005), with lesions ≥24mm predicting shorter progression-free survival (HR 3.93;p<0.001). Endoscopic submucosal dissection (ESD) and modified-endoscopic mucosal resection (m-EMR) were associated with a significantly longer progression-free survival (p=0.004). R0 resection showed a borderline protective effect. Five-year overall survival approached 95%. Conclusions. T1g-NETs>1cm frequently recur and may exhibit aggressive potential, particularly when lesions are larger. When endoscopic resection is feasible, ESD or m-EMR should be preferred to optimize outcomes.