Staging is the process of finding out how far a cancer has spread. The stage (extent) of bile duct cancer is one of the most important factors in selecting treatment options and estimating a patient's outlook for recovery and survival (prognosis).

A staging system is a standardized way for members of the cancer care team to summarize the extent of a cancer's spread. The stage of a cancer is determined by the results of the physical exam, testing (such as imaging and other tests), and by the results of surgery if it has been done.

The American Joint Committee on Cancer (AJCC) TNM system

The major 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.

Intrahepatic bile duct cancers (those starting within the liver) are staged separately from extrahepatic bile duct cancers. Also, extrahepatic bile duct cancers are split into 2 groups: perihilar tumors and distal tumors. The TNM system for all bile duct cancers contains 3 key pieces of information:

• T describes whether the main 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 located 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:

• The numbers 0 through 4 indicate increasing severity.
• The letter X means "cannot be assessed" because the information is not available.

Intrahepatic bile duct cancer

T categories

TX: No description of the tumor's extent is possible because of incomplete information.

T0: There is no evidence of a primary tumor.

Tis: Cancer cells are only growing in the mucosa (the innermost layer of the bile duct) and have not invaded deeper layers of the bile duct. This stage is also known as intramucosal carcinoma and was previously called carcinoma in situ.

T1: A single tumor that has grown into deeper layers of the bile duct wall, but it is still only in the bile duct. The cancer has not grown into any blood vessels.

T2: Split into 2 groups

T2a: A single tumor that has grown through the wall of the bile duct and into a blood vessel.

T2b: 2 or more tumors, which may (or may not) have grown into blood vessels

T3: The cancer has grown into nearby structures such as the intestine, stomach, common bile duct, abdominal wall, diaphragm, or lymph nodes around the portal vein.

T4: The cancer is spreading through the liver by growing along the bile ducts.

N categories

NX: Regional (nearby) lymph nodes cannot be assessed.

N0: The cancer has not spread to nearby lymph nodes.

N1: The cancer has spread to nearby lymph nodes.

M categories

MX: Distant spread (metastasis) cannot be assessed.

M0: The cancer has not spread to tissues or organs far away from the bile duct.

M1: The cancer has spread to tissues or organs far away from the bile duct.

Stage grouping

Once a patient's T, N, and M categories have been determined, this information is combined in a process called stage grouping. The stage is expressed in Roman numerals from stage 0 (the least advanced stage) to stage IV (the most advanced stage). Some stages are subdivided with letters.

Stage 0 (Tis, N0, M0): The cancer is only growing in the innermost layer of the bile duct (Tis) and has not spread to lymph nodes (N0) or distant sites (M0).

Stage I (T1, N0, M0): The cancer is a single tumor that has grown into deeper layers of the bile duct wall (T1), but it has not grown into any blood vessels. It has not spread to lymph nodes or distant sites.

Stage II (T2, N0, M0): The cancer is either a single tumor that has grown into a blood vessel (T2a) or there are multiple tumors (T2b). The cancer has not grown into any nearby organs or structures. It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage III (T3, N0, M0): The cancer has grown into nearby structures such as the duodenum (first part of the small intestine), colon, stomach, abdominal wall, diaphragm, or lymph nodes around the portal vein (T3). It has not (N0) spread to nearby lymph nodes or distant sites.

Stage IV

Stage IVA (T4, N0, M0) OR (Any T, N1, M0): Either the cancer is spreading through the liver by growing along the bile ducts, OR the cancer has spread to nearby lymph nodes. It has not spread to distant sites.

Stage IVB (Any T, any N, M1): The cancer has spread to distant sites (M1).

Extrahepatic bile duct cancer of the perihilar bile ducts

T categories for perihilar bile duct cancer

TX: No description of the tumor's extent is possible because of incomplete information.

T0: There is no evidence of a primary tumor.

Tis: Cancer cells are only growing in the mucosa (the innermost layer of the bile duct) and have not invaded deeper layers of the bile duct. This stage is also known as intramucosal carcinoma and was previously called carcinoma in situ.

T1: The cancer has grown into deeper layers of the bile duct wall, such as the muscle layer or the fibrous tissue layer.

T2: The tumor has grown through the wall of the bile duct and into nearby tissue.

T2a: The tumor has grown through the wall of the bile duct and into surrounding fat.

T2b: The tumor has grown through the wall of the bile duct and into nearby liver tissue.

T3: The cancer is growing into branches of the main blood vessels of the liver on one side (the main blood vessels of the liver are the portal vein and the hepatic artery).

T4: The cancer is growing into the main blood vessels of the liver (the portal vein and or the common hepatic artery) or branches of these vessels on 2 sides, OR the cancer is growing directly into other bile ducts while part of the tumor is growing into one of the main blood vessels.

N categories for perihilar bile duct cancer

NX: Regional (nearby) lymph nodes cannot be assessed.

N0: The cancer has not spread to nearby lymph nodes.

N1: The cancer has spread to nearby lymph nodes, such as those along the cystic duct, the common bile duct, the hepatic artery, and the portal vein.

N2: The cancer has spread to lymph nodes further away from the tumor, such as those around the major blood vessels of the abdomen (such as the aorta, the vena cava, the celiac artery, and the superior mesenteric artery).

M categories

MX: Distant spread (metastasis) cannot be assessed.

M0: The cancer has not spread to tissues or organs far away from the bile duct.

M1: The cancer has spread to tissues or organs far away from the bile duct.

Stage grouping

Once a patient's T, N, and M categories have been determined, this information is combined in a process called stage grouping. The stage is expressed in Roman numerals from stage 0 (the least advanced stage) to stage IV (the most advanced stage). Some stages are subdivided with letters.

Stage 0 (Tis, N0, M0): Cancer cells are only growing in the mucosa (the innermost layer of the bile duct) and have not invaded deeper layers of the bile duct. Cancer has not spread to nearby lymph nodes or distant sites.

Stage I (T1, N0, M0): The cancer has grown into deeper layers of the bile duct wall, such as the muscle layer or the fibrous tissue layer. It has not spread to nearby lymph nodes or distant sites.

Stage II (T2, N0, M0): The tumor has grown through the wall of the bile duct and into surrounding fat (T2a) or liver tissue (T2b). Cancer has not spread to nearby lymph nodes or distant sites.

Stage III: Split into 2 substages:

Stage IIIA (T3, N0, M0): The cancer is growing into branches of the main blood vessels of the liver (the portal vein and/or the hepatic artery) on one side (T3). Cancer has not spread to nearby lymph nodes or distant sites.

Stage IIIB (T1 to T3, N1, M0): The cancer has grown into deeper layers of the bile duct wall (T1) and may have grown through the wall and into nearby fat or liver tissue (T2). The cancer may be growing into branches of the main blood vessels of the liver on one side (T3). Cancer cells are found in nearby lymph nodes (N1), but the cancer has not spread to distant sites (M0).

Stage IV: Split into 2 substages:

Stage IVA (T4, N0-1, M0): The cancer is growing into the main blood vessels of the liver (the portal vein and or the common hepatic artery), is growing into branches of these vessels on 2 sides, or part of the cancer is growing directly into other bile ducts while another part of the tumor is growing into one of the main blood vessels (T4). The cancer may have spread to nearby lymph nodes (N0 or N1), but it has not spread to distant sites.

Stage IVB (any T, N2, M0) or (any T, any N, M1): The cancer has either spread to lymph nodes away from the tumor (N2) or it has spread to distant sites (tissues or organs away from the bile duct) such as the lungs or bones (M1).

Distal extrahepatic bile duct cancer

T categories for distal extrahepatic bile duct cancer

TX: No description of the tumor's extent is possible because of incomplete information.

T0: There is no evidence of a primary tumor.

Tis: Cancer cells are limited to the mucosa (the innermost layer of the bile duct) and have not invaded deeper layers of the bile duct. This stage is also known as intramucosal carcinoma and was previously called carcinoma in situ.

T1: The cancer has grown into deeper layers of the bile duct wall, but it is still only in the bile duct.

T2: The cancer has grown through the bile duct wall but has not started growing into nearby structures.

T3: The cancer has grown into nearby structures such as the liver, gallbladder, pancreas, or duodenum (the first part of the small intestine), but it is not growing into the main blood vessels supplying the stomach and intestines (the celiac artery and the superior mesenteric artery).

T4: The cancer has grown into one or both of the main blood vessels supplying the stomach and intestines (the celiac artery and the superior mesenteric artery).

N categories for distal extrahepatic bile duct cancer

NX: Regional (nearby) lymph nodes cannot be assessed.

N0: The cancer has not spread to nearby lymph nodes.

N1: The cancer has spread to nearby lymph nodes.

M categories for distal extrahepatic bile duct cancer

MX: Distant spread (metastasis) cannot be assessed.

M0: The cancer has not spread to tissues or organs far away from the bile duct.

M1: The cancer has spread to tissues or organs far away from the bile duct.

Stage grouping

Once a patient's T, N, and M categories have been determined, this information is combined in a process called stage grouping. The stage is expressed in Roman numerals from stage 0 (the least advanced stage) to stage IV (the most advanced stage). Some stages are subdivided with letters.

Stage 0 (Tis, N0, M0): The cancer is only growing in the innermost layer of the bile duct (Tis) and has not spread to lymph nodes (N0) or distant sites (M0).

Stage IA (T1, N0, M0): The cancer has grown into deeper layers of the bile duct wall (T1), but it has not grown all the way through the wall. It has not spread to lymph nodes or distant sites.

Stage IB (T2, N0, M0): The cancer has grown through the bile duct (T2) but has not invaded nearby organs or structures and has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage IIA (T3, N0, M0): The cancer has grown into nearby structures such as the liver, gallbladder, pancreas, or duodenum (the first part of the small intestine), but it is not growing into the main blood vessels supplying the stomach and intestines (the celiac artery and the superior mesenteric artery) (T3). It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage IIB (T1 to T3; N1; M0): The cancer may or may not have spread outside of the bile duct to nearby organs. It has spread into nearby lymph nodes (N1) but not to distant sites.

Stage III (T4, any N, M0): The cancer has grown into one or both of the main blood vessels supplying the stomach and intestines (the celiac artery and the superior mesenteric artery) (T4). It may (N1) or may not (N0) have spread to nearby lymph nodes but has not spread to distant sites.

Stage IV (Any T, any N, M1): The cancer has spread to distant sites (M1).

Resectable versus unresectable cancers

The TNM system divides bile duct cancers into several groups that help give doctors an idea about a person's prognosis (outlook). But for treatment purposes, doctors often use a simpler system based on whether these cancers are likely to be resectable (able to be completely removed by surgery) or unresectable. In general terms, most stage III and IV tumors are unresectable, but there may be exceptions. Resectability is based on the size and location of the tumor, how far it has spread, and whether or not a person is healthy enough to have surgery.

Survival statistics for bile duct cancers

Survival rates are a way for doctors to discuss and compare the prognosis (outlook) for patients, based on the stage of the cancer or other traits. Accurate survival rates can be hard to determine for bile duct cancers because these cancers are not common. Some of the more important factors affecting survival include the location and extent of the cancer, whether or not it is resectable, and a person's general health.

There are some important points to note about the survival rates below:

• These statistics come from the National Cancer Institute's SEER program. SEER does not separate these cancers by AJCC stage, but instead puts them into 3 groups: localized, regional, and distant. Localized is like AJCC stage I. Regional includes stages II and III. Distant means the same as stage IV.

• The 5-year survival rate refers to the percentage of patients who live at least 5 years after being diagnosed. Of course, some of these patients live much longer than 5 years after diagnosis. Relative survival rates assume that some people will die of other causes and compare the observed survival with that expected for people without the cancer. This is a more accurate way to describe the prognosis for patients with a particular type and stage of cancer.

• These numbers are among the most current we have available, but they represent people who were first diagnosed and treated several years ago. Because of improvements in treatment since then (including more aggressive surgery), survival rates for people now being diagnosed with these cancers may be higher.

• Survival statistics can sometimes be useful as a general guide, but they may not accurately represent any one person's prognosis. A number of other factors, including other tumor characteristics, how the cancer was treated, and a person's age and general health, can also affect outlook. Your doctor is likely to be a good source as to whether these numbers may apply to you, as he or she is familiar with the aspects of your particular situation.

Intrahepatic bile duct cancer

Extrahepatic blie duct cancer

Last Medical Review: 01/21/2010
Last Revised: 01/21/2010