Metastasis Prevalence and Survival of Patients with T1-2 Gastric Neuroendocrine Tumor Treated with Endoscopic Therapy and Surgery.

Background And Aim: The selection criteria and long-term outcomes of endoscopic therapy (ET) for gastric neuroendocrine tumors (G-NETs) remain controversial.

Methods: Using Surveillance, Epidemiology, and End Results (SEER) Program database, we assessed the prevalence of metastasis of early G-NETs and long-term outcomes of ET in G-NET patients with good/moderate differentiation and no muscularis propria (MP) involvement.

Results: A total of 2207 patients with stage T1 and T2 G-NETs were included. The depth of invasion into MP [odds ratio (OR) 4.581, 95% confidence interval (CI) 2.571-8.162; P < 0.001] and size of > 20 mm (OR 5.656, 95% CI 2.002-15.975; P = 0.001) were significantly associated with metastasis. The 5-year overall survival (OS) and cancer-specific survival (CSS) of the ET group were similar to the surgery group (91.11% vs. 91.09%, P = 0.750; 99.26% vs. 99.01%, P = 0.173). In the multivariable Cox proportional hazards regression models adjusting for age, gender, race, year of diagnosis, SEER region, depth of tumor invasion, site of cancer, tumor size, and chemotherapy, procedures employed (ET or surgery) had no significant impact on the OS [hazard ratio (HR) 1.189; 95%CI 0.721-1.961; P = 0.498] and CSS (HR 0.684; 95% CI 0.021-22.727; P = 0.832).

Conclusions: The long-term outcome of survival did not appear to differ between ET and surgery in G-NETs with good/moderate differentiation, ≤ 20 mm size, and no MP involvement.