Incidence, patterns of care and prognostic factors for outcome of gastroenteropancreatic neuroendocrine tumors (GEP-NETs): results from the National Cancer Registry of Spain (RGETNE)

Background: Neuroendocrine tumors (NETs) are an unusual family of neoplasms with a wide and complex spectrum of clinical behavior. Here, we present the first report of a National Cancer Registry of gastroenteropancreatic neuroendocrine tumors from a Southern European country. Patients and methods: Data was provided online at www.retegep.net by participating centers and assessed for internal consistency by external independent reviewers. Results: The study cohort comprised 907 tumors. The most common tumor types were carcinoids (55%), pancreatic nonfunctional tumors (20%), metastatic NETs of unknown primary (9%), insulinomas (8%) and gastrinomas (4%). Forty-four percent presented with distant disease at diagnosis, most often those from small intestine (65%), colon (48%), rectum (40%) and pancreas (38%), being most unusual in appendix primaries (1.3%). Stage at diagnosis varied significantly according to sex, localization of primary tumor, tumor type and grade. Overall 5-year survival was 75.4% (95% confidence interval 71.3% to 79.5%) and was significantly greater in women, younger patients and patients with hormonal syndrome and early stage or lower grade tumors. Prognosis also differed according to tumor type and primary tumor site. However, stage and Ki-67 index were the only independent predictors for survival. Conclusion: This national database reveals relevant information regarding epidemiology, current clinical practices and prognosis of NETs in Spain, providing valuable insights that may contribute to understand regional disparities in the incidence, patterns of care and survival of this heterogeneous disease across different continents and countries.