Carcinoid tumors and small-cell carcinomas of the gallbladder and extrahepatic bile ducts: a comparative study based on 221 cases from the Surveillance, Epidemiology, and End Results Program.

Primary neuroendocrine tumors of the gallbladder (GB) and extrahepatic biliary ducts (EHBDs) include carcinoid tumors and small-cell carcinomas (SCCs). They are uncommon, and therefore, little is known about their demographics and clinical course. From National Cancer Institute's Surveillance, Epidemiology, and End Results program (1973-2005), we analyzed the demographics and 10-year relative survival rates of carcinoids and SCCs of the GB and EHBD according to histologic type and stage. There were 119 cases of carcinoid tumors and 54 cases of SCCs in the GB. There were 31 carcinoid tumors and 17 SCCs in the EHBD. The female/male ratios of carcinoids in the GB and EHBD were 2.4 and 1.6, respectively. The ratios for SCC in the GB and EHBD were 2.2 and 1.1, respectively. For the GB, the mean age of diagnosis for carcinoids was 64.5, and for SCC, it was 67.5. For the EHBD, the mean age was 58.2 for carcinoids and 68.4 for SCC. The 10-year survival rates were 36% for carcinoid tumors of the GB and 80% for carcinoid tumors of the EHBD. For SCC, the 10-year survival was 0% in the GB and EHBD. Carcinoid tumors and SCC of the extrahepatic biliary tree are uncommon neoplasms that differ in their demographics and biologic behavior, supporting the distinction of these 2 histopathologic types. Therefore, these tumors should be separately classified and not included in the single generic group of neuroendocrine carcinoma.