TNM breast cancer staging
This page tells you about the staging of breast cancer, including TNM staging. You can find information about
What is staging?
The staging system normally used in breast cancer is called TNM, which stands for ‘tumour, node, metastasis’. So TNM staging takes into account the size of the tumour, whether the lymph nodes are affected, and whether cancer has spread to other parts of the body (metastasis). The stage is important because it helps your breast cancer specialist to decide on the best treatment for you.
The TNM stages of breast cancer
The T stages are numbered 1 to 4 and describe the size of the tumour. The N stages are numbered 0 to 3. They describe which lymph nodes are affected, if any. The M stages are M0 (no sign of cancer spread) and M1 (cancer has spread to another part of the body apart from the lymph nodes under the arm).
How TNM fits together
Your doctor will put these 3 stages together to give you your overall stage. So, for example, you might see a tumour described as T2 N0 M0. This would be a single tumour 2 - 5 cm across, with no evidence of spread to any lymph nodes and no evidence of spread outside the breast.
You can view and print the quick guides for all the pages in the Treating breast cancer section.
Early breast cancer means the cancer has not spread beyond the breast or the lymph nodes in the armpit on the same side of the body. So, the cancer has not spread to any other part of the body. Cancer that has come back in the area of the breast after treatment is called local recurrence.
You may hear the term locally advanced breast cancer. This means the cancer has not spread to another part of the body but may be
- Bigger than 5 cm across
- Growing into the skin or muscle of the chest
- Present in the lymph nodes in the armpit, and these lymph nodes are either stuck to each other, or to other structures
Secondary breast cancer is also called metastatic breast cancer or stage 4 breast cancer. It means that the cancer has spread to other parts of the body, such as the liver or bones.
The stage of a cancer tells the doctor how far the cancer has spread. The tests and scans you have when diagnosing your cancer give some information about the stage. The stage is important because it helps your breast cancer specialist to decide on the best treatment for you. They usually make decisions about treatment for breast cancer according to the TNM stage and the grade of the cancer. TMN staging takes into account the size of the tumour (T), whether the lymph glands (lymph nodes) are affected (N) and whether the tumour has spread anywhere else in the body (M for metastases).
Doctors also sometimes use the number system of staging or a formula called the Nottingham Prognostic Indicator (NPI) to give some idea of how well treatment may work for an individual person with breast cancer and how long the person may live. You can read more about the Nottingham Prognostic Index (NPI) in this section.
TX means that the tumour size cannot be assessed
T1 - The tumour is no more than 2 centimetres (cm) across
T1 is further divided into 4 groups
- T1mic - under a microscope the cancer cells can be seen to spread less than 0.1cm into surrounding tissue (microinvasion)
- T1a - the tumour is more than 0.1 cm but not more than 0.5 cm
- T1b - the tumour is more than 0.5 cm but not more than 1 cm
- T1c - the tumour is more than 1 cm but not more than 2 cm
T2 - The tumour is more than 2 centimetres, but no more than 5 centimetres across
T3 - The tumour is bigger than 5 centimetres across
T4 is divided into 4 groups
- T4a - The tumour has spread into the chest wall
- T4b - The tumour has spread into the skin
- T4c - The tumour is fixed to both the skin and the chest wall
- T4d - Inflammatory carcinoma - this is a cancer in which the overlying skin is red, swollen and painful to the touch
NX means that the lymph nodes cannot be assessed (for example, if they were previously removed)
N0 - No cancer cells found in any nearby nodes
N1 - Cancer cells are in nodes in the armpit but the nodes are not stuck to surrounding tissues
N2 is divided into 2 groups
- N2a - there are cancer cells in the lymph nodes in the armpit, which are stuck to each other and to other structures
- N2b - there are cancer cells in the lymph nodes behind the breast bone (the internal mammary nodes). These have either been seen on a scan or felt by the doctor. There is no evidence of cancer in lymph nodes in the armpit
N3 is divided into 3 groups
- N3a - there are cancer cells in lymph nodes below the collarbone
- N3b - there are cancer cells in lymph nodes in the armpit and under the breast bone
- N3c - there are cancer cells in lymph nodes above the collarbone
M0 - No sign of cancer spread
M1 - Cancer has spread to another part of the body, apart from the breast and lymph nodes under the arm
Your doctor will put these 3 stages together to give you your overall stage. This is usually what the doctor will write on your test forms. So, for example, you might see a tumour described as T2 N0 M0. This would be
- A single tumour 2 to 5 cm across
- No evidence of spread to any lymph nodes
- No evidence of spread outside the breast
If you would like more information about anything to do with the stages of breast cancer, you can contact one of the breast cancer organisations. You can find detailed information about the number system of staging in this CancerHelp UK section. And more about staging cancers generally in our about cancer section.
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