Stages and grading

When breast cancer is diagnosed, it is important to know the stage and grade of the cancer. This helps your doctors decide on the best treatment for you. The stage of a cancer describes its size and whether it has spread from where it started. The grade of a cancer describes how the cancer cells look compared to normal cells and how quickly they grow.

The most common systems to describe the stage of a cancer are number staging and TNM staging:

  • Number staging describes breast cancer in stages. These go from stage 0 (the cancer cells are in the ducts of the breast) through to stage 4 (the cancer has spread to other parts of the body).
  • TNM staging looks at the size of the cancer, whether it has spread to the lymph nodes or to other parts of the body.

To grade a breast cancer, a doctor examines a sample of the cancer cells under a microscope. They grade the cells from grades 1–3, or from low-grade to high-grade.

Staging, grading and receptors for breast cancer

Your breast specialist needs certain information about the cancer to help plan the most appropriate treatment for you. This includes the stage of the cancer, its grade and whether it has receptors for hormones, proteins, or both. Your breast specialist and breast care nurse will talk this over with you.

Your surgeon won’t know the exact stage of the cancer until after your operation and when the results of all your tests are ready.


Staging

The stage of a cancer is a term used to describe its size and whether it has spread beyond the area of the body where it started.

Breast cancer can be divided into number stages. This is to measure the size of the cancer (lump), and whether it has spread to the lymph nodes or another part of the body.

Stage 0 – this describes non-invasive breast cancers. Ductal carcinoma in situ (DCIS) is sometimes described as stage 0. DCIS can almost always be cured.

The following stages are known as invasive breast cancer:

Stage 1 – the cancer (lump) is 2cm or smaller and has not spread to the lymph nodes in the armpit.

Stage 2 is divided into two stages:

  • Stage 2A – the lump is smaller than 2cm and has spread to lymph nodes in the armpit OR it’s bigger than 2cm (but under 5cm) and hasn’t spread to the lymph nodes OR the cancer can’t be found in the breast but is in the lymph nodes in the armpit.
  • Stage 2B – the lump is smaller than 5cm and has spread to the lymph nodes in the armpit OR it’s bigger than 5cm but hasn’t spread to the lymph nodes in the armpit.

Stage 3 is divided into three stages:

  • Stage 3A – the cancer can’t be found in the breast or the lump is under 5cm, and the cancer is in the lymph nodes in the armpit, which are stuck together OR the lump is bigger than 5cm and has spread to the lymph nodes.
  • Stage 3B – the cancer has spread to tissue near the breast and may be attached to surrounding skin or muscle. There are usually cancer cells in the lymph nodes in the armpit as well.
  • Stage 3C – the cancer has spread to lymph nodes in the armpit, below the breastbone, near the neck or under the collarbone.

Stage 4 – the cancer has spread to other parts of the body such as the bones, liver or lungs. This is called secondary or metastatic breast cancer.


TNM staging

This number stage is then combined with a letter system called TNM, which 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 is no lymph nodes affected while N1 means there are cancer cells in the lymph nodes.

M describes if 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.


Other terms used

You may hear other terms used to describe breast cancer:

  • Early breast cancer is a term often used to describe stage 1 and 2 breast cancer.
  • Locally advanced breast cancer is a term sometimes used to describe stage 3 breast cancers.
  • Local recurrence means the cancer has come back in the breast area after treatment.
  • Secondary, advanced or metastatic breast cancer means it has spread to other parts of the body.


Grading

Grading is about how the cancer cells look under the microscope compared with normal cells. The grade helps your doctor to decide if you need further treatment after surgery.

  • Grade 1 or low-grade or well differentiated - The cancer cells look similar to normal cells and usually grow slowly and are less likely to spread.
  • Grade 2 or moderate-or intermediate-grade - The cancer cells look more abnormal and are slightly faster growing.
  • Grade 3 or high-grade or poorly differentiated - The cancer cells look very different from normal cells and may grow more quickly.


Back to Understanding your diagnosis

Just been diagnosed

Just been diagnosed with cancer? We're here for you every step of the way. There are many ways we can help.

Treatment overview

Most men will have surgery to remove the cancer. You may also have other treatments to reduce the risk of it coming back.