Stage IIIB includes: T1-3, N1, M0. T1: Tumor confined to the bile duct, with extension up to the muscle layer or fibrous tissue. T2a: Tumor invades beyond the wall of the bile duct to surrounding adipose tissue. T2b: Tumor invades adjacent hepatic parenchyma. T3: Tumor invades unilateral branches of the portal vein or hepatic artery. N1: Regional lymph node metastasis (including nodes along the cystic duct, common bile duct, hepatic artery, and portal vein). M0: No distant metastasis. (from AJCC 7th Ed.) [from NCI]