Staging and grading

Staging and grading for breast cancer

Your specialist 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 HER 2.

This information comes from the results of the tests you have had, including:

  • the biopsy, when the tissue was examined
  • other tests that were done on the cells.

Your specialist doctor and 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, which you can download, to make them easier to understand.

This information is about stage 1 to 3 breast cancer. If you have stage 4 breast cancer, you may find our information about secondary breast cancer helpful.


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.

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Treatment overview

Women usually have surgery to remove the cancer – you may also have other treatments to reduce the risk of it coming back.