Intrahepatic bile duct cancer starts in the bile ducts in the liver. Find out about how doctors stage and grade this type of bile duct cancer.
The stage of a cancer tells you how far it has grown or spread. The grade describes how abnormal the cancer cells are compared to healthy cells.
The stage and grade are important because your specialist uses this information to decide which treatment is most suitable for you.
Your scans and tests will give some information about the stage and grade of your cancer.
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 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 describes how far the cancer (tumour) has grown. There are 5 main T stages for bile duct cancer – Tis to T4.
Tis means the tumour is only within the top layers of cells lining the bile duct.
T1 means there is one tumour that is contained within the bile duct, but has grown deeper into the wall of the bile duct.
T2 is split into 2 groups - T2A and T2B. T2A means there is one tumour and it has grown through the wall of the bile duct into a nearby blood vessel. T2B means there is more than one tumour which may or may not have grown into a nearby blood vessel.
T3 means the tumour has either grown into the covering of the liver (the peritoneum) or has grown into nearby structures outside the liver, such as the bowel.
T4 means the tumour has spread into the liver by growing along the ducts.
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 describes whether the cancer has spread (metastasised) to another part of the body. 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 away from the bile duct.
There are 4 main number stages of intrahepatic bile duct cancer - stage 1 to stage 4:
Stage 1 means there is only one tumour and it is completely inside the bile duct.
Stage 2 means one of the following:
- there is one tumour and it has grown into a nearby blood vessel
- there is more than one tumour which may or may not have grown into a nearby blood vessel
Stage 3 means one of the following:
- the tumour has grown into the covering of the liver (the peritoneum)
- it has grown into nearby structures outside the liver such as the bowel
Stage 4 means that the cancer is advanced. There are 2 main groups within stage 4 cancer- stage 4a and stage 4b.
Stage 4a means one of the following:
- the tumour has grown around the bile duct and may have spread along the duct but is not in the lymph nodes
- the tumour is any size and there are cancer cells in the lymph nodes but it hasn’t spread any further
Stage 4b means that the cancer has spread to another part of the body, away from the bile ducts.
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 also 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 4 grades of intrahepatic bile duct cancer - grade 1 to grade 4:
Grade 1 cancer means the cancer cells look very like normal bile duct cells. This is called low grade cancer.
Grade 2 cancer means the cancer cells look a bit abnormal. This is called intermediate grade cancer.
Grade 3 cancer means the cancer cells look abnormal and unlike normal bile duct cells. This is called high grade cancer.
Grade 4 cancer means the cancer cells look very abnormal and completely different to normal bile duct cancer cells. This is also called high grade cancer.
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
- grade 4 cancer cells as undifferentiated.