From a clinical and practical point of view, extrahepatic bile duct cancers can be considered to be localized (resectable) or unresectable. This has obvious prognostic importance.
Localized extrahepatic bile duct cancer
Patients with localized extrahepatic bile duct cancer have cancer that can be completely removed by the surgeon. These patients represent a very small minority of cases of bile duct cancer and usually are those with a lesion of the distal common bile duct where 5-year survival rate of 25% may be achieved. Extended resections of hepatic duct bifurcation tumors (Klatskin tumors, also known as hilar tumors) to include adjacent liver, either by lobectomy or removal of portions of segments 4 and 5 of the liver, may be performed. There has been no randomized trial of adjuvant therapy for patients with localized disease. Radiation therapy (external-beam radiation with or without brachytherapy), however, has been reported to improve local control.[1,2][Level of evidence: 3iiiDiii]
Unresectable extrahepatic bile duct cancer
Patients with unresectable extrahepatic bile duct cancer have cancer that cannot be completely removed by the surgeon. These patients represent the majority of patients with bile duct cancer. Often the cancer invades directly into the portal vein, the adjacent liver or along the common bile duct, and to adjacent lymph nodes. Spread to distant parts of the body is uncommon but intra-abdominal metastases, particularly peritoneal metastases, do occur. At this stage, patient management is directed at palliation.
The TNM staging system should be used when staging the disease of a patient with extrahepatic bile duct cancer. Most cancers are staged following surgery and pathologic examination of the resected specimen. Evaluation of the extent of disease at laparotomy is most important for staging.
Staging depends on imaging, which often defines the limits of the tumor, and surgical exploration with pathologic examination of the resected specimen. In many cases, it may be difficult to completely resect the primary tumor.
Definitions of TNM
The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification to define extrahepatic bile duct cancer.[3,4] Stages defined by TNM classification apply to all primary carcinomas arising in the extrahepatic bile duct or in the cystic duct and do not apply to intrahepatic cholangiocarcinomas, sarcomas, or carcinoid tumors.[3,4]
Tables 1, 2, 3, and 4 pertain to the perihilar bile duct group.
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.|
|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.|