Bile duct cancer stages

How is bile duct cancer staged?

The TNM system, established by the American Joint Committee on Cancer, is commonly used to stage bile duct cancer (cholangiocarcinoma). The TNM system uses three key factors to determine a cancer’s stage:

T (tumor): This describes the size of the original tumor.

N (node): This indicates whether the cancer is present in the lymph nodes.

M (metastasis): This refers to whether cancer has spread to other parts of the body.

A number (0-4) or the letter X is assigned to each factor. A higher number indicates increasing severity. For instance, a T1 score indicates a smaller tumor than a T2 score. The letter X means the information could not be assessed.

Staging varies depending on the type of bile duct cancer. For instance, doctors will stage intrahepatic bile duct cancer that starts inside the liver, differently than perihilar bile duct cancer, which starts just outside the liver, or distal bile duct cancer, which starts further down the bile duct.

Stages of bile duct cancer

Once the T, N and M scores have been assigned, the cancer is staged accordingly:

Stage 0

The cancer is found only in the innermost layer of the bile duct (mucosa) and has not spread to the deeper layers. In this stage, the disease has not invaded lymph nodes or any other distant sites in the body.

Stage 1 bile duct cancer

Still contained within the bile duct, the cancer now extends into the deeper layers of the bile duct wall (muscle or fibrous tissue layer). It has not spread to lymph nodes or other distant sites.

Stage 2 bile duct cancer

The cancer has now spread through the wall of the bile duct into nearby fat (2B) or liver tissue (2B).

Stage 3 bile duct cancer

Stage 3 bile duct cancer is divided into two subcategories:

• Stage 3A: The disease has spread to the main portal vein, the common hepatic artery, duodenum (first part of the small intestine), colon, stomach or abdominal wall, but not beyond. The cancer has not spread to the lymph nodes or distant sites.
• Stage 3B: Cancer cells are found in nearby lymph nodes, but the cancer has not spread to distant sites.

Stage 4 bile duct cancer

• Stage 4A: The cancer is growing and has spread to the main blood vessel and the lymph nodes but not distant sites.
• Stage 4B: The cancer has either spread to lymph nodes away from the tumor or it has spread to distant sites.

What happens in the final stages of bile duct cancer?

In most cases, advanced-stage bile duct cancer (stages 3 and 4) is unresectable, meaning that it cannot be completely removed by surgery because the cancer is too widespread or difficult to access. Usually, this means treatment will be focused on reducing symptoms and preventing further cancer spread.

Symptoms related to bile duct cancer often don’t occur until the cancer has advanced and blocked the passage of bile from the liver to the gallbladder or small intestine.

When the bile duct is blocked, patients may notice such symptoms as:

• Yellowing of the skin and eyes (jaundice)
• Itchiness
• Greasy or pale stools
• Darkened urine

Advanced bile duct cancers are also likely to cause stomach pain due to large tumors.

Bile duct cancer survival rate

A cancer’s stage is an important metric in predicting patient outcomes. Each stage of cancer is given an average relative survival rate, which is usually based on the number of people with a certain type and stage of cancer who live five or more years after their diagnosis. Survival rates may provide helpful context, but they don’t tell the full story. They are only estimates that reflect average outcomes of patients in the past.

According to the American Cancer Society (ACS), approximately 8,000 bile duct cancers are diagnosed in the United States each year. The outcomes of these patients depend on the stage and type of bile duct cancer (intrahepatic and extrahepatic) and individual factors, such as age and medical history.

According to the ACS, for intrahepatic bile duct cancer, the overall five-year relative survival rate across all stages is 9 percent, and for extrahepatic bile duct cancer, it’s 10 percent.

However, as noted, survival rates vary depending on the stage:

• Localized intrahepatic bile duct cancers, which have not spread outside of the bile ducts (stages 0 and 1), have a five-year relative survival rate of 24 percent.
• For distant intrahepatic bile duct cancers, which have spread to distant areas or organs (stage 4B), the five-year relative survival rate is 2 percent.
• Distant extrahepatic bile duct cancers have a five-year relative survival rate of 2 percent, compared to a 17 percent relative survival rate for localized extrahepatic bile duct cancers.

Next topic: How is bile duct cancer diagnosed?