Biliary Tract Cancers

Epidemiology: Biliary tract cancers (BTCs) are malignancies that include cholangiocarcinoma (CCA) and gallbladder cancer (GBC) [1, 2]. BTCs account for nearly 3% of all cancers [1] with a mortality rate of 3.58 deaths per 100,000 [3]. According to AJCC, the 5-year survival rates were 50%, 30%, 10%, and 0% for patients with stages I, II, III, and IV, respectively [1]. Among the three subtypes of CCAs that were classified based on the anatomic site of origin, perihilar cholangiocarcinoma (PCCA) accounts for 50–60%, distal cholangiocarcinoma (DCCA) constitutes 20–30%, and intrahepatic cholangiocarcinoma (ICCA) accounts for 10–20% of all cases [4]. PCCA and DCCA together constitute extrahepatic cholangiocarcinomas (ECCA) [1, 2]. The 5-year survival rates were 10%, 11%, and 8% for PCCA, DCCA, and ICCA, respectively [4]. Interestingly, the incidence of CCA is as high as 85 cases per 100,000 in Southeast Asia, which can be attributed to liver fluke parasites [2–4].