Staging is a way of describing a cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.
One tool that doctors use to describe the stage is the TNM system. This system uses three criteria to judge the stage of the cancer: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to other parts of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer so doctors can work together to plan the best treatments.
TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:
- How large is the primary tumor and where is it located? (Tumor, T)
- Has the tumor spread to the lymph nodes? (Node, N)
- Has the cancer metastasized to other parts of the body? (Metastasis, M)
Intrahepatic bile duct cancer is staged using the same system as liver cancer. The staging of both intrahepatic and extrahepatic bile duct cancer is below.
Intrahepatic bile duct cancer staging
Tumor. Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Some stages are also divided into smaller groups to help describe the tumor in even more detail. If there is more than one tumor, the lowercase letter "m" (multiple) is added to the "T" category. Specific tumor stage information is listed below:
TX: The primary tumor cannot be evaluated.
T0: There is no evidence of a primary tumor.
T1: The tumor is only a single tumor. It has not spread to adjacent blood vessels.
T2: Either of these conditions:
- Any tumor that has spread to adjacent blood vessels.
- Multiple tumors, none larger than 5 centimeters (cm).
T3: Either of these conditions:
- More than one tumor larger than 5 cm.
- The tumor has spread to the major veins within the liver.
T4: Either of these conditions:
- The tumor has spread to the organs near the liver (except the gallbladder).
- The tumor has spread through the visceral peritoneum (layer of tissue that lines the abdomen).
Node. The "N" in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the site of the cancer are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The regional lymph nodes cannot be evaluated.
N0: Cancer has not spread to the regional lymph nodes.
N1: The cancer has spread to the regional lymph nodes.
Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread to other parts of the body.
MX: The tumor cannot be evaluated.
M0: The cancer has not metastasized.
M1: There is metastasis to another part of the body.
Cancer stage grouping for intrahepatic bile duct cancer
Doctors assign the stage of the cancer by combining the T, N, and M classifications:
Stage I: This is the earliest stage of intrahepatic bile duct cancer. The tumor has not spread to the blood vessels, lymph nodes, or other parts of the body (T1, N0, M0).
Stage II: The tumor has spread to nearby blood vessels, but has not spread to the regional lymph nodes or other parts of the body (T2, N0, M0).
Stage IIIA: The cancer has not spread beyond the liver, but the area of the cancer is larger than stage I or II, and it often has invaded nearby blood vessels (T3, N0, M0).
Stage IIIB: The cancer has spread to organs near the liver, but has not spread to nearby lymph nodes or other parts of the body (T4, N0, M0).
Stage IIIC: Any tumor that has spread to the regional lymph nodes, but not to other parts of the body (any T, N1, M0).
Stage IV: Any tumor that has spread to other parts of the body (any T, any N, M1).
Recurrent: Recurrent intrahepatic bile duct cancer is cancer that comes back after treatment.
Extrahepatic bile duct cancer staging
Tumor. Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe the stage of extrahepatic bile duct cancer. Some stages are also divided into smaller groups that help describe the tumor in even more detail. If there is more than one tumor, the lowercase letter "m" is added to the "T" category. Specific tumor stage information is listed below:
TX: The primary tumor cannot be evaluated.
T0: There is no evidence of a primary tumor.
Tis: Refers to carcinoma (cancer) in situ. Cancer is only in a single layer of cells lining the bile duct and has not invaded other parts of the bile duct wall.
T1: The tumor is located only in the bile duct.
T2: The tumor has spread beyond the wall of the bile duct.
T3: The tumor has spread to the liver, gallbladder, pancreas, and/or a unilateral branch (a single side) of the veins and/or arteries within the liver.
T4: The tumor has spread bilaterally (both sides) to the veins or arteries within the liver and/or adjacent structures, such as the colon, stomach, duodenum, or abdominal wall.
Node. The "N" in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the site of the cancer are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The regional lymph nodes cannot be evaluated.
N0: Cancer has not spread to the regional lymph nodes.
N1: The cancer has spread to the regional lymph nodes.
Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread to other parts of the body.
MX: The tumor cannot be evaluated.
M0: The cancer has not metastasized.
M1: There is metastasis to another part of the body.
Cancer stage grouping for extrahepatic bile duct cancer
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage 0: This is the earliest stage of extrahepatic bile duct cancer. The cancer is only found in one layer of cells, and has not spread (Tis, N0, M0).
Stage IA: The tumor is confined to the bile duct (T1, N0, M0).
Stage IB: The tumor has spread beyond the wall of the bile duct, but has not spread to the regional lymph nodes or other parts of the body (T2, N0, M0).
Stage IIA: The tumor has invaded adjacent organs, such as the liver, gallbladder, pancreas, and/or unilateral branches of adjacent blood vessels, but has still not spread to the regional lymph nodes or other parts of the body (T3, N0, M0).
Stage IIB: The tumor may or may not have invaded unilateral branches of adjacent blood vessels and/or the tumor has spread to nearby organs, such as the liver, gallbladder, and pancreas. The cancer has spread to nearby lymph nodes, but has not spread to other parts of the body (T1 or T2 or T3, N1, M0).
Stage III: The tumor has spread bilaterally to adjacent blood vessels and/or adjacent structures, and may or may not have spread to the regional lymph nodes, but has not spread to other parts of the body (T4, any N, M0).
Stage IV: Any tumor that has spread to other parts of the body (any T, any N, M1).
Recurrent: Recurrent extrahepatic bile duct cancer is cancer that comes back after treatment.
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Sixth Edition (2002) published by Springer-Verlag New York, www.springer-ny.com.
Last Updated: April 16, 2008
