Forty-Year Trends in Cholangiocarcinoma Incidence in the U.S.: Intrahepatic Disease on the Rise

Challenges in the diagnosis and classification of cholangiocarcinoma have made it difficult to quantify the true incidence of this highly aggressive malignancy.

We analyzed the Surveillance, Epidemiology, and End Results data to assess long-term trends in the age-standardized incidence of intrahepatic and extrahepatic cholangiocarcinoma between 1973 and 2012, correcting for systematic coding errors. Because intrahepatic cholangiocarcinoma (ICC) may frequently be misdiagnosed as cancer of unknown primary (CUP), we also analyzed trends in the incidence of CUP.