Current surgical treatment strategies for hepatocellular carcinoma in North America

Table 1 American liver tumor study group modified tumor-node-metastasis staging classification for hepatocellular carcinoma

Tumor classification	Definition	Stage	Criteria
T0, N0, M0	No tumor found
T1	1 nodule < 2.0 cm	Stage I	T1 lesion
T2	1 nodule 2-5 cm, 2 or 3 nodules each less than 3 cm	Stage II	T2 lesion
T3	1 nodule > 5 cm, 2 or 3 nodules, at least 1 > 3 cm	Stage III	T3 lesion
T4a	≥ 4 nodules, any size	Stage IVa1	T4a
T4b	T2, T3 or T4a plus gross intrahepatic, portal or hepatic vein involvement as indicated by CT, MRI or US	Stage IVa2	T4b
N1	Regional (porta hepatis) node involvement	Stage IVb	Any N1 or M1
M1	Metastatic disease including extrahepatic portal or hepatic vein involvement

HCC: Hepatocellular carcinoma; CT: Computed tomography; MRI: Magnetic resonance imaging; US: Ultrasound; TNM: Tumor node metastasis.