AJCC 8 th edition staging system for pathologically versus clinically staged intrahepatic cholangiocarcinoma (iCCA): ready for prime time?

Biliary tract cancers (BTC) are a rare, heterogeneous group of malignancies that arise from the neoplastic proliferation of cholangiocytes or epithelium of the bile ducts (1). They are comprised of three anatomic subgroups: intrahepatic cholangiocarcinoma (iCCA), extrahepatic cholangiocarcinoma (EHCC), and cancers of the gallbladder. In patients who present with early stage disease, patients are offered a potential curative treatment through surgical resection. Our increased understanding of the biology of these diseases has allowed us to understand the heterogeneity that exists between these anatomic subgroups (2), which is observed from the differences in prognosis and clinical outcomes.