Year: 2020
Type: article
Abstract: Cholangiocarcinomas (CCAs) are rare tumors that originate from cholangiocytes in the bile ducts and are classified as intra-or extrahepatic (ICC or ECC).ICCs account for 10-12% of liver cancers, while ECCs account for approximately one-third of biliary tract cancers (1).Incidence rates of CCA are geographically variable, with the highest rates in Asia.However, even in the highest incidence country (South Korea) the rates are only 2.8 and 2.2 per 100,000 personyears for ICC and ECC, respectively (2).Incidence rates of both ICC and ECC have been increasing in most countries globally, which potentially indicates a changing etiology (2).There are few established risk factors for CCA, including chronic conditions-primary sclerosing cholangitis and Caroli's disease-and, in Asian countries, liver flukes and hepatolithiasis.However, the rarity of CCA makes elucidating the etiology of these tumors challenging.Compounding the challenges in studying CCA etiology is the evolving ICD coding over time, which has resulted in misclassification of perihilar or Klatskin tumors, which are ECCs arising proximal to the cystic duct (3).In response to these issues, we have conducted large, pooled analyses of prospective cohort studies-the Liver Cancer Pooling Project (LCPP) and the Biliary Tract Cancers Pooling Project (BiTCaPP).These pooling projects have allowed us to examine harmonized risk factors for ICC and ECC, with a focus on Western populations.In the BiTCaPP, we identified cigarette smoking and obesity, but not alcohol consumption, as etiologic factors that increase ECC risk (4,5).In the LCPP, we identified excess alcohol consumption, cigarette smoking, diabetes
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W3011453752