Intrahepatic cholangiocarcinoma: the AJCC/UICC 8th edition updates.

Intrahepatic cholangiocarcinoma accounts for 5% to 30% of all primary liver cancers, and its incidence has increased in the last 3 decades. Surgical resection remains the only potentially curative treatment but is associated with high tumor recurrence rates. The 7th edition of the American Joint Committee on Cancer (AJCC) Staging Manual introduced a new staging system for intrahepatic cholangiocarcinoma, which was previously staged the same as hepatocellular carcinoma. The recently published 8th edition has subdivided the T1 category to T1a and T1b based on a size cutoff of 5 cm, removed periductal invasion from the T4 category, and downstaged T4 tumors and regional lymph node metastasis from stage IV to IIIB. Continued international efforts to accurately stratify prognosis are important to counsel patients and guide treatment decisions.