Cholangiocarcinoma: the quest for a second-line systemic treatment

Biliary tract cancer (BTC) is the second most common primary liver malignancy (10,000 and 12,000 new cases/year in Europe and the United States, respectively) after hepatocellular carcinoma (HCC) (1,2). BTCs are a heterogeneous group of epithelial neoplasms (adenocarcinoma in 90% of cases), and are classified into four subtypes based on their anatomical origin: (I) peripheral or intrahepatic cholangiocarcinoma (iCCA), developed within the hepatic parenchyma; (II) perihilar cholangiocarcinoma, most frequent, also known as Klatskin tumors (pCCA), between the second-order bile ducts and the cystic duct; (III) distal cholangiocarcinoma (dCCA), located on the main bile duct below the bifurcation of the cystic duct, which are often grouped with pCCAs under the appellation extrahepatic cholangiocarcinoma (eCCA); (IV) and gallbladder carcinoma (3,4)