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Intrahepatic stages and grades

Intrahepatic bile duct cancer starts in the bile ducts in the liver. Find out how doctors stage and grade this type of bile duct cancer. 

Diagram showing the position of the intraheptic bile ducts

The stage of a cancer tells you its size and whether it has spread. Your doctor looks at your scans and x-rays to work out the stage. This helps them to decide what treatment you need.

The grade describes how abnormal the cancer cells are compared to healthy cells. A specialist doctor (pathologist) works out the grade by looking at a sample of cells under the microscope.

Bile duct cancer is also known as cholangiocarcinoma. There are different ways of staging the different types of bile duct cancer. For intrahepatic bile duct cancer doctors use the:

  • TNM system
  • number staging system

TNM staging

TNM stands for Tumour, Node and Metastasis. The system describes: 

  • how far the primary tumour has grown (T)
  • whether the cancer has spread to the lymph nodes (N)
  • whether the cancer has spread to a different part of the body (M)

T stages

T describes how far the cancer (tumour) has grown. There are 4 main T stages for bile duct cancer – T1 to T4.

T1 is split into 2 groups. T1a means there is only one tumour and it is 5cm or less. T1b means there is only one tumour and it is bigger than 5cm.

T2 means that there is only one tumour and it has grown into nearby blood vessels. Or there is more than one tumour.

T3 means the tumour has grown through the lining covering the liver (the visceral peritoneum).

T4 means the tumour has grown into nearby structures outside the liver, such as the bowel.

N stages

N describes whether the cancer has spread to the lymph nodes. There are 2 stages - N0 and N1. 

N0 means there are no cancer cells in the lymph nodes.

N1 means there are cancer cells in the lymph nodes.

M stages

M describes whether the cancer has spread to another part of the body (metastases). There are 2 stages - M0 and M1.

M0 means there is no sign of cancer spread.

M1 means the cancer has spread to other parts of the body, such as the lungs.

Number stages

There are 4 main number stages of intrahepatic bile duct cancer - stage 1 to stage 4:

Stage 1

Stage 1 is split into two groups:

Stage 1A means there is only one tumour and is no more than 5cm. It has not grown into any nearby blood vessels or spread anywhere else. This is the same as T1a, N0, M0 in the TNM staging system.

Stage 1B means there is only one tumour and it is bigger than 5cm. It has not grown into any nearby blood vessels. This is the same as T1b, N0, M0.

Stage 2

Stage 2 means there is only one tumour and it has grown into nearby blood vessels. Or there is more than one tumour. This is the same as T2, N0, M0.

Stage 3

Stage 3 is divided into two groups:

Stage 3A means the tumour has grown through the covering of the liver (the visceral peritoneum). This is the same as T3, N0, M0.

Stage 3B means the tumour has grown into nearby structures outside the liver such as the bowel. This is the same as T4, N0, M0.

Or it means the tumour has spread to the nearby lymph nodes. This is the same as Any T, N1, M0.

Stage 4

Stage 4 means that the cancer has spread to other areas of the body such as the lungs. This is the same as Any T, Any N, M1.

Grades of intrahepatic bile duct cancer

The grade of a cancer is a way of measuring how abnormal cancer cells are compared to healthy cells. It gives an idea of how quickly a cancer may grow and whether it is likely to spread.

Low grade cancers are usually slower growing and less likely to spread. High grade cancers tend to be faster growing and more likely to spread.

There are 3 grades of intrahepatic bile duct cancer – grade 1 to grade 3:

Grade 1

Grade 1 cancer means the cancer cells look similar to normal bile duct cells. This is called low grade cancer.

Grade 2

Grade 2 cancer means the cancer cells look a bit abnormal. This is called intermediate grade cancer.

Grade 3

Grade 3 cancer means the cancer cells look very abnormal and unlike normal bile duct cells. This is called high grade cancer.

Differentiation

Differentiation means how developed or mature a cell is. Cancer cells are not as mature as normal cells.

You may hear your doctor describe:

  • grade 1 cancer cells as well differentiated
  • grade 2 cancer cells as moderately differentiated
  • grade 3 cancer cells as poorly differentiated
Last reviewed: 
05 Feb 2018
  • AJCC Cancer Staging Manual (8th edition)
    M Amin and others 
    Springer, 2017.

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