Analysis of influencing factors of metastasis and survival difference after endoscopic and surgical treatment in patients with gastric neuroendocrine tumors in stage T_1-2

Objective To explore the metastasis rate of gastric neuroendocrine tumors (G-NETs) patients in stage T_1~2 and its related risk factors, and to compare the long-term survival results of patients after endoscopic therapy (ET) and surgical treatment.

Methods The data in SEER database were analyzed, and 1 258 patients with pathologically diagnosed G-NETs from January 1, 2004 to December 31, 2015 were included. Logistic regression was used to analyze the influencing factors of metastasis of patients with G-NETs. In patients with T_1~2N₀M₀ stage G-NETs, the general clinical characteristics of patients receiving ET or surgery were compared after propensity matching analysis. The difference of 5-year overall survival (OS) and the risk factors affecting OS between the surgery and ET groups were analyzed by Kaplan-Meier survival curve and Cox proportional hazard regression model.

Results A total of 851 patients with T₁ and T₂ G-NETs were followed up for 5 years. Lymph node or distant metastasis occurred in 183 patients (21.5%). The metastasis rates of T₁ and T₂ G-NETs patients were 14.6% and 33.3%, respectively (P < 0.05). Multivariate logistic regression analysis showed that tumor grade G_3/4, invasion of lamina propria and tumor diameter > 20 mm were closely related to metastasis of T_1~2 stage G-NETs. The 5-year survival rate of patients in non-metastasis group (n＝668) was 85.1%, and that of patients in metastasis group (n＝183) was 34.7% (P < 0.05). Subgroup analysis showed that during the 5-year follow-up, the average survival time of patients with metastasis after surgery and ET treatment was 42.0 months and 31.3 months (χ²＝14.510, P < 0.05), and the average survival time of patients without metastasis after surgery and ET treatment was 53.2 months and 52.3 months (χ²＝0.279, P＝0.598). After propensity matching analysis, the 5-year survival rate of patients with T_1~2N₀M₀ G-NETs was similar after ET and surgery (88.8% vs 89.4%, χ²＝0.22, P＝0.882). Multivariate Cox proportional hazard regression model showed that age, histological grade and depth of invasion were related to OS of patients with T_1~2N₀M₀ G-NETs.

Conclusions The tumor grade G_3/4, invasion of lamina propria and tumor diameter > 20 mmmight be closely related to the metastasis of G-NET in T_1~2 stage, the prognosis of these patients with metastasis is poor. 5-year survival rate in patients with T_1~2N₀M₀ G-NETs are similar after ET and surgery.