Table 1. Primary Tumor (T)a
| a Reprinted with permission from AJCC: Perihilar bile ducts. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 219-25. | |
| 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 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. |
| T4 | Tumor invades main portal vein or its branches bilaterally; or the common hepatic artery; or the second-order biliary radicals bilaterally; or unilateral second-order biliary radicals with contralateral portal vein or hepatic artery involvement. |
