Prevalence of Neuroendocrine Tumors in the Gastrointestinal and Hepatobiliary Systems

Background: Carcinoid tumors are the most common neuroendocrine tumors. In recent years, these tumors have had an increasein incidence, which is probably due to a higher number of them being incidentally found as a result of the rise of preventivemedicine.Objectives: This study aimed to analyze a series of digestive carcinoid tumors detected by conventional endoscopy and/or echoendoscopyto evaluate the prevalence of those located in the colon and rectum, and subsequently make a comparison with data availablein the literature.Methods: In this retrospective, multicenter study (two centers), the clinical records of 100 white patients with more than 100 digestivecarcinoid tumors (some multiple) diagnosed from 1994 to 2018 were reviewed.Results: The mean age of presentation was 52 years and 57% of the patients were men. The mean tumor size was 10 mm. The localizationof the tumors was: stomach 43% (n = 43); duodenum 5% (n = 5); intestine 8% (n = 8); appendix 14% (n = 14); colon 4% (n = 4);rectum 19% (n = 19); pancreas 3% (n = 3); liver 2% (n = 2); gallbladder 1% (n = 1); primary tumor of unknown origin 1% (n = 1). Mostmultifocal tumors were in the stomach (20%; n = 20), followed by the duodenum (1%; n = 1) and intestine (1%; n = 1). Metastases andcarcinoid syndrome were observed in 6% and 5% of the cases, respectively. General survival at the closure of the study was 80%.Conclusions: Age and sex were similar to those described in the literature, while the colon and rectum represented 23% of all carcinoidtumors. There was a predominance of gastroduodenal and rectal carcinoid tumors, probably because the series analyzedwas essentially endoscopic. In comparison with the literature, less cases of metastases or carcinoid syndrome were recorded andsurvival was greater, perhaps due to earlier diagnosis and treatment.