Secular Trends in the Incidence of Cholangiocarcinoma in the USA and the Impact of Misclassification

Background and Aims It has been reported that the incidence of intrahepatic cholangiocarcinoma (ICC) has increased in the USA, while extrahepatic cholangiocarcinoma (ECC) has decreased or remained stable. However, neither the recent trends nor the effects of the misclassification of Klatskin tumors are known.