Your cancer doctor needs certain information about the cancer to advise you on the best treatment for you. This includes:
- the stage of the cancer
- the grade of the cancer
- whether the cancer has receptors (proteins) for hormones or a protein called HER2.
This information comes from the results of all the tests you have had, including:
- the biopsy, when the tissue was examined
- other tests that were done on the cells.
Your cancer doctor and specialist nurse will talk to you about this. They will explain how it helps you and your doctor decide on your treatment plan.
The stage of a cancer describes its size and whether it has spread from where it started. There are different systems for describing the stage of a cancer. The most commonly used ones are the TNM staging system and the number staging system.
The TNM staging system
The TNM staging system gives the complete stage of the cancer:
- T describes the size of the tumour.
- N describes whether the cancer has spread to the lymph nodes and which nodes are involved. For example, N0 means no lymph nodes are affected. N1 means there are cancer cells in 1 to 3 of the lymph nodes.
- M describes whether the cancer has spread to another part of the body. For example, M0 means the cancer has not spread (metastasised) to other parts of the body.
Sometimes the final TNM staging may not be certain until after surgery to remove the cancer.
The number staging system
Breast cancer can also be divided into four number stages. We have put these into a table to make them easier to understand. You can download it here.
This information is about stage 1 to 3 breast cancer.
- Stage 1 breast cancer is when the cancer is 2cm or smaller. There may be no cancer cells in the lymph nodes in the armpit or tiny numbers of cancer cells (micrometastasis) are found. Sometimes the cancer cannot be found in the breast, but cancer cells have spread to lymph nodes in the armpit.
- Stage 2 breast cancer is when the cancer is up to or bigger than 5cm. It may or may not have spread to the lymph nodes under the arm. Sometimes the cancer cannot be found in the breast. But cancer cells have spread to 1 to 3 lymph nodes in the armpit or near the breast bone.
- Stage 3 breast cancer is sometimes called locally advanced breast cancer. The cancer has spread to the lymph nodes in the armpit and sometimes to other lymph nodes nearby. It may have spread to the skin of the breast or to the chest muscle. The skin may be red, swollen or have broken down. Sometimes the cancer cannot be found in the breast or is small but has spread to 4 to 9 lymph nodes in the armpit.
Stage 4 breast cancer is also called secondary or metastatic breast cancer. This is when breast cancer has spread to other parts of the body. We have separate information about secondary breast cancer.
The grade of a cancer gives an idea of how slowly or quickly it might grow. The grade is based on how the cancer cells look under a microscope compared with normal cells. The cells are examined by a doctor called a pathologist, who studies tissue samples and is an expert in cell types.
Grade 1 (low-grade cancer)
The cancer cells look similar to normal cells (they are well differentiated). They usually grow slowly. These cancer cells are less likely to spread.
Grade 2 (moderate or intermediate-grade cancer)
The cancer cells look more abnormal and grow slightly faster than grade 1 cells.
Grade 3 (high-grade cancer)
The cancer cells look very different from normal cells (they are poorly differentiated). They may grow more quickly than grade 1 or 2 cells.