Clinicopathologic characteristics and prognosis of gastroenteropancreatic neuroendocrine neoplasms: a multicenter study in South China

Background: Gastroenteropancreatic neuroendocrine neoplasms(GEP-NENs) are a heterogeneous group of rare tumors. Many issues in terms of epidemiologic features, pathogenesis, and treatment of GEP-NENs are still under discussion. Our study aimed to analyze the clinicopathologic characteristics and prognosis of Chinese patients with GEP-NENs.Methods: Complete clinicopathologic data and survival information of 1183 patients with GEP-NENs treated between 2005 and 2015 were collected from five medical centers in Guangdong Province, China. Patient survival was estimated using the Kaplan–Meier method and analyzed using the log-rank test; prognostic factors were analyzed using the Cox proportional hazards model.Results: The most common tumor location was the rectum(37.4%), followed by the pancreas(28.1%), stomach(20.7%), small intestine(7.2%), appendix(3.4%), and colon(3.3%). After initial definitive diagnosis, 1016(85.9%) patients underwent surgery. The 1-, 3-, and 5-year overall survival(OS) rates for the entire cohort were 87.9%, 78.5%, and 72.8%, respectively. The 3-year OS rates of patients with G1, G2, and G3 tumors were 93.1%, 82.7%, and 43.1%, respectively(P < 0.001). The 3-year OS rates of patients with stage I, II, III, and IV tumors were 96.0%, 87.3%, 64.0%, and 46.8%, respectively(P < 0.001). Patients with distant metastasis who underwent palliative surgery had a longer survival than those who did not(P = 0.003). Similar survival benefits of palliative surgery were observed in patients with neuroendocrine tumor(P y, M category, and sur= 0.031) or neuroendocrine carcinoma(P gery were found to be independent prog= 0.046). In multivariate analysis, age, grade, N categornostic factors.Conclusions: Patients with GEP-NENs who are women, younger than 50 years old, have smaller tumor size, have lower tumor grade, have lower T/N/M category, and who undergo surgery can have potentially longer survival time. Our data showed that surgery can improve the prognosis of GEP-NEN patients with distant metastasis. However, randomized controlled trials need to be conducted to establish the optimal criteria for selecting patients to undergo surgery.