Introduction Cholangiocarcinoma is an aggressive and rare cancer of the bile duct with a very poor prognosis. It accounts for approximately three percent of gastrointestinal cancers but nearly 20 percent of deaths are from hepatobiliary cancers. Cholangiocarcinoma is also a clinically silent disease that presents at advanced stages. In this study, we wanted to identify subpopulations at the greatest risk of developing cholangiocarcinoma such that we can improve diagnosis and ultimately reduce the cancer mortality rate. Methods The United States Cancer Registry (USCS) was used to obtain data for cholangiocarcinoma from 2001 to 2015. Incidence analysis was done for sex, race, stage, primary location (intrahepatic bile duct or extrahepatic bile duct), and US regional location. Results The overall incidence of cholangiocarcinoma from 2001 to 2015 was 1.26 per 100,000 people per year. The overall incidence rates were greatest for each stratification in males, Asian and Pacific Islanders (API), distant disease, intrahepatic bile duct cholangiocarcinoma (ICC), and in the Northeast. Incidence rates were increasing between 2001 and 2015 in all subpopulations. Compared to extrahepatic bile duct cholangiocarcinoma (ECC), ICC increased significantly between 2001 and 2015. From 2001 to 2007, the annual percent change (APC) for ICC was 2.79, from 2007 to 2010 the APC was 17.02, and from 2010 to 2015 the APC was 9.67. Moreover, the incidence of distant disease also increased significantly with an APC of 9.22. Conclusion In our study, we analyzed the incidence of cholangiocarcinoma in all 50 states in the USA. We found that the incidence is increasing in all subpopulations and specifically at a dramatic rate for ICC and those with distant disease at the time of diagnosis. Ultimately, our findings identified at-risk populations who need closer monitoring for cholangiocarcinoma.
Keywords: cancer; cholangiocarcinoma; epidemiology; gastroenterology; hepatology.