There are three different staging systems for bile duct cancers, depending on where the cancer started: Intrahepatic bile duct cancers (those starting within the liver) Perihilar (hilar) bile duct cancers (those starting in the hilum, the area just outside the liver) Distal bile duct cancers (those starting farther down the bile duct system)

The earliest stage for intrahepatic bile duct cancers is stage 0 (also called carcinoma in situ, or CIS). Stages then range from stage I (1) through stage IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means the cancer has spread more.