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 increase in incidence, which is probably due to a higher number of them being incidentally found as a result of the rise of preventive medicine. Objectives: This study aimed to analyze a series of digestive carcinoid tumors detected by conventional endoscopy and/or echoendoscopy to evaluate the prevalence of those located in the colon and rectum, and subsequently make a comparison with data available in the literature. Methods: In this retrospective, multicenter study (two centers), the clinical records of 100 white patients with more than 100 digestive carcinoid 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 localization of 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). Most multifocal tumors were in the stomach (20%; n = 20), followed by the duodenum (1%; n = 1) and intestine (1%; n = 1). Metastases and carcinoid 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 carcinoid tumors. There was a predominance of gastroduodenal and rectal carcinoid tumors, probably because the series analyzed was essentially endoscopic. In comparison with the literature, less cases of metastases or carcinoid syndrome were recorded and survival was greater, perhaps due to earlier diagnosis and treatment.