Table 3.

TNM and American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) Staging Systems for Perihilar Cholangiocarcinoma

TNM stage	Criteria
Tx	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in situ
T1	Tumor confined to the bile duct, with extension up to the muscle layer of fibrous tissue
T2a	Tumor invades beyond the wall of the bile duct to surrounding adipose tissue
T2b	Tumors invades adjacent hepatic parenchyma
T3	Tumor invades unilateral branches of the portal vein or hepatic artery
T4	Tumor invades main portal vein or its branches bilaterally OR tumor invades the common hepatic artery OR tumor invades second-order biliary radicals bilaterally or tumor invades unilateral second-order biliary radicals with contralateral portal vein ORhepatic artery involvement
Nx	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastases
N1	Regional lymph node metastases (incl. nodes along the cystic duct, common bile duct, hepatic artery and portal vein)
N2	Metastases to periaortic, pericaval, superior mesenteric artery, and/or celiac artery lymph nodes
M0	No distant metastases
M1	Distant metastases
AJCC/UICC stage	Tumor	Node	Metastasis
0	Tis	N0	M0
I	T1	N0	M0
II	T2a–b	N0	M0
III A	T3	N0	M0
III B	T1–3	N1	M0
IV A	T4	N0–1	M0
IV B	Any T	N2	M0
	Any T	Any N	M1

TNM, tumor, node, metastasis.