Objective  To explore the clinical and pathological characteristics and prognostic factors of gastric neuroendocrine carcinoma（G-NEC）and gastric mixed adenoendocrine carcinoma（G-MANEC）.

  Methods  Retrospective analysis was conducted on the clinical data of 67 patients with G-NEC and G-MANEC who underwent surgical treatment at Heping Hospital Affiliated to Changzhi Medical College from May 2015 to May 2023. The study included an analysis of the pathological characteristics distinguishing G-NEC from G-MANEC.

  Results  Compared to gastric adenocarcinoma, patients with G-NEC and G-MANEC in the stomach showed a higher incidence of gastric cancer in the male gastric cardia and were diagnosed at a later age. Tumors with larger diameters increase susceptibility to anemia, low albumin levels, and invasion of nerves and vasculature. Deeper tumor infiltration is associated with increased local lymph node metastases, later TNM staging, and a higher likelihood of distant metastasis post-surgery. The prognosis of G-NEC and G-MANEC is worse than that of gastric adenocarcinoma (P=0.001). However, there is no statistically significant difference in the pathological characteristics (P>0.05) and prognosis analysis (P=0.212) between G-NEC and G-MANEC. Univariate survival analysis identified age, preoperative albumin, preoperative CEA, number of lymph node metastases, TNM staging, and postoperative distant metastasis as risk factors affecting patient’s overall survival (OS). In the multivariate analysis, age, preoperative albumin, TNM staging, and postoperative distant metastasiswere identified as independent risk factors for OS.

  Conclusions  There is a significant difference in clinical characteristics between G-NEC, G-MANEC, and gastric adenocarcinoma, often diagnosed at an advanced stage, which is prone to distant metastasis post-surgery. Poor prognosis is observed in patients aged over 60 years, with preoperative albumin<40g/L, TNM stage Ⅱ/Ⅲ, and postoperative distant metastasis.