title: Risk factors for cholangiocarcinoma.
abstract: Cholangiocarcinoma (CC) is the second most common primary hepatic malignancy after hepatocellular cancer. CC accounts for approximately 10%-25% of all hepatobiliary malignancies. There are considerable geographic and demographic variations in the incidence of CC. There are several established risk factors for CC, including parasitic infections, primary sclerosing cholangitis, biliary-duct cysts, hepatolithiasis, and toxins. Other less-established potential risk factors include inflammatory bowel disease, hepatitis C virus, hepatitis B virus, cirrhosis, diabetes, obesity, alcohol drinking, tobacco smoking, and host genetic polymorphisms. In studies where the distinction between intra- and extrahepatic CC was used, some potential risk factors seem to have a differential effect on CC, depending on the site. Therefore, the consistent use of a more refined classification would allow a better understanding of risk factors for CC.
authors.affiliation: Section of Gastroenterology at the Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Gia L
authors.initials: GL
authors.lastname: Tyson
authors.forename: Hashem B
authors.initials: HB
authors.lastname: El-Serag
mesh_terms: D001650:Bile Duct Neoplasms / Q000453:epidemiology*; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000145:classification / Q000453:epidemiology* / Q000209:etiology; D015209:Cholangitis, Sclerosing / Q000150:complications; D015529:Choledochal Cyst / Q000150:complications; D006801:Humans; D010272:Parasitic Diseases / Q000150:complications; D012307:Risk Factors