117MO Comparison of survival and patterns of recurrence in gastric neuroendocrine carcinoma, mixed adenoneuroendocrine carcinoma and adenocarcinoma: A multicenter study from China

Abstract

Gastric neuroendocrine carcinoma (G-NEC) and mixed adenoneuroendocrine carcinoma (G-MANEC) are rare pathological types of gastric cancer, and there is a lack of multicenter studies comparing the prognosis and recurrence patterns of G-NEC, G-MANEC and gastric adenocarcinoma (G-AC). Patients with resectable G-NEC and G-MANEC at 23 hospitals in China from January 2006 to December 2016 were identified. In addition, 2,785 patients with G-AC were selected as controls. Propensity score-matched analysis was used to match stage among the different pathological types, and disease-free survival (DFS), postrecurrence survival (PRS) and patterns of recurrence were examined. We reviewed 3,689 patients: 503 of with G-NEC, 401 with G-MANEC and 2,785 with G-AC. After propensity score matching, the DFS and PRS of G-NEC and G-MANEC were significantly worse than those of G-AC (all P<0.05). Multivariable analyses revealed that G-NEC and G-MANEC (vs. G-AC) were independent risk factors for DFS and PRS (all P<0.05). Compared with G-AC patients, G-NEC and G-MANEC patients were more likely to have distant recurrence (P<0.05). On multivariate analysis, G-NEC and G-MANEC were independent predictors for distant recurrence (both P<0.001). Additionally, T3-T4 stage and lymph node metastasis were independent risk factors for distant recurrence of G-NEC and G-MANEC (both P<0.05). G-NEC and G-MANEC have worse prognoses and are more prone to distant recurrence than G-AC. Thus, different follow-up and treatment strategies should be developed for G-NEC and G-MANEC, especially patients with tumors penetrating into the subserosa or deeper layers and with lymph node metastasis.