There is geographical variation in the prevalence of bile duct cancers, with South East Asia having a much higher prevalence. This is felt to be due to increased prevalence of chronic bile duct infection with Clonorchis sinensis and Opisthorchis viverrini. In Western countries potential predisposing factors include inflammatory bowel disease and primary sclerosing cholangitis, congenital choledochal cysts and possibly exposure to some environmental toxins such as dioxins, asbestos, nitrosamines and Thorotrast.

There are no published recommendations regarding screening or prevention in the general population. Differentiation of malignant versus benign biliary tract strictures can be difficult.

The incidence of cholangiocarcinoma in patients with underlying primary sclerosing cholangitis is around 9-40%. In these patients it can be particularly difficult to identify malignant transformation. Although controversial, the routine use of CA 19-9 serum antigen monitoring is recommended by some, with quoted sensitivity of 75% and specificity of 80% for a CA 19-9 level > 100 U/mL. FDG PET scan is also being explored in this context.