How is Bile Duct Cancer Staged?
The stage of a cancer describes how far it has spread. The stage of bile duct cancer is one of the most important factors in selecting treatment options and estimating a patient’s outlook (prognosis).
The stage is determined by the results of the physical exam, imaging and other tests (described in the section “ How is bile duct cancer diagnosed?”), and by the results of surgery if it has been done.
The American Joint Committee on Cancer (AJCC) TNM system
A staging system is a standard way for the cancer care team to sum up the extent of a cancer. The main system used to describe the stages of bile duct cancer is the American Joint Committee on Cancer (AJCC) TNM system. There are actually 3 different staging systems for bile duct cancers, depending on where they start:
No matter where they are, nearly all bile duct cancers start in the innermost layer of the wall of the bile duct. Over time they can grow through the wall toward the outside of the bile duct. If a tumor grows through the bile duct wall, it can invade (grow into) nearby blood vessels, organs, or other structures. It might also enter the nearby lymphatic or blood vessels, from which it can spread to nearby lymph nodes or to other parts of the body.
The TNM system for all bile duct cancers contains 3 key pieces of information:
- T describes whether the main (primary) tumor has invaded through the wall of the bile duct and whether it has invaded other nearby organs or tissues.
- N describes whether the cancer spread to nearby (regional) lymph nodes (bean-sized collections of immune system cells throughout the body).
- M indicates whether the cancer has metastasized (spread) to other organs of the body. (The most common sites of bile duct cancer spread are the liver, peritoneum [the lining of the abdominal cavity], and the lungs.)
Numbers or letters appear after T, N, and M to provide more details about each of these factors.
Last Medical Review: November 1, 2014 Last Revised: January 20, 2016