Clinicopathological Features and Prognostic Factors of Gastroenteropancreatic Neuroendocrine Tumors: A Single-Center Experience

IntroductionGastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of neoplasms with increasing incidence and variable clinical characteristics. This study aimed to describe the clinicopathological characteristics of surgically/endoscopically treated GEP-NETs and identify prognostic factors associated with overall survival (OS) in a single tertiary center.MethodsIn this retrospective, single-center cohort study, we reviewed the data of adult patients diagnosed with GEP-NETs and treated at the Department of General Surgery, Marmara University School of Medicine, between January 2018 and December 2024. Demographic, clinical, and pathological variables were collected, including histologic type (NET vs. NEC), tumor grade, tumor size, Ki-67 index, mitotic index, nodal status, and stage. The OS was analyzed using the Kaplan-Meier method and compared using the log-rank test. Cox proportional hazards models were used to identify the independent mortality predictors.ResultsAmong the 96 patients included in the final analysis, 55% were female, with a median age of 55 years. The primary tumor sites were the pancreas (46%) and stomach (35%), followed by the appendix (6%), small intestine (5%), colorectal (3%), and hepatobiliary tract (4%). Surgical resection and lymph node dissection were performed in 90% and 72% of patients, respectively. NET and NEC accounted for 71% and 29%, respectively. Grades were G1 (48%), G2 (22%), G3 (16%), MiNEN (8%), and undefined (6%). The 5-year OS for the cohort was 79%. Patients with pancreatic and gastric tumors, higher-grade tumors, larger tumors, elevated Ki-67/mitotic indices, NEC histology, and advanced stage had significantly worse survival. In the multivariate analysis, older age, NEC histology, and advanced stage remained independent adverse prognostic factors.ConclusionIn this single-center experience, GEP-NET prognosis was primarily driven by age, histologic type, and disease stage. These findings may support risk-adapted, multidisciplinary management tailored to tumor biology and disease extent.