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Stage 3

Find out what stage 3 breast cancer is and about treatment options.

Stage 3 means that the cancer has spread from the breast to lymph nodes close to the breast or to the skin of the breast or to the chest wall.

It is also called locally advanced breast cancer.

Stage 3 breast cancer is divided into 3 groups.

Stage 3A

Stage 3A means one of the following:

  • no tumour is seen in the breast or the tumour may be any size and cancer is found in 4 to 9 lymph glands under the arm or in the lymph glands near the breastbone
Diagram 1 of 3 showing stage 3A breast cancer
  • the tumour is larger than 5cm and small clusters of breast cancer cells are in the lymph nodes
Diagram 2 of 3 showing stage 3A breast cancer
  • the tumour is more than 5cm and has spread into up to 3 lymph nodes in the armpit or to the lymph nodes near the breastbone
Diagram 3 of 3 showing stage 3A breast cancer

Stage 3B

Stage 3B means the tumour has spread to the skin of the breast or the chest wall. The chest wall means the structures surrounding and protecting the lungs, such as the ribs, muscles, skin or connective tissues. The cancer has made the skin break down (an ulcer) or caused swelling. The cancer may have spread to up to 9 lymph nodes in the armpit or to the lymph nodes near the breastbone.

Diagram 1 of 2 showing stage 3B breast cancer

Cancer that has spread to the skin of the breast might be an inflammatory breast cancer.

Diagram 2 of 2 showing stage 3B breast cancer

Stage 3C

Stage 3C means the tumour can be any size, or there may be no tumour. But there is cancer in the skin of the breast, causing swelling or an ulcer and it has spread to the chest wall. It has also spread to one or more of the following structures:

  • 10 or more lymph nodes in the armpit
Diagram 1 of 3 showing stage 3C breast cancer
  • lymph nodes above or below the collar bone
Diagram 2 of 3 showing stage 3C breast cancer
  • lymph nodes in the armpit and near the breastbone
Diagram 3 of 3 showing stage 3C breast cancer

For treatment, doctors divide stage 3C breast cancer into cancers that can be operated on (operable breast cancers) and those that can't (inoperable cancer).

TNM stages

The TNM staging system stands for Tumour, Node, Metastasis.

  • T describes the size of the tumour
  • N describes whether there are any cancer cells in the lymph nodes
  • M describes whether the cancer has spread to a different part of the body

In the TNM staging system stage 3A breast cancer is the same as:

  • T0 N2 M0
  • T1 N2 M0
  • T2 N2 M0
  • T3 N1 M0
  • T3 N2 M0

Stage 3B is the same as:

  • T4 N0 M0
  • T4 N1 M0
  • T4 N2 M0

Stage 3C is the same as:

  • Any T N3 M0

Treatment

You might have drug treatments such as chemotherapy or a targeted cancer drug as a first treatment. This is followed by surgery and then more drug treatments. 

Or you might have surgery as a first treatment followed by chemotherapy or other drug treatments.

Drug treatment before surgery

You might have chemotherapy as a first treatment to shrink the cancer down.

If your cancer cells have particular proteins called HER2 receptors you might also have a targeted cancer drug called trastuzumab (Herceptin).

These treatments might shrink the tumour enough to allow your surgeon to remove just the area of cancer. This is called a wide local excision or lumpectomy. If the cancer doesn’t shrink enough, you need to have the whole breast removed. This is called a mastectomy.

Your surgeon will also remove lymph nodes from under the arm to check for cancer cells. 

You usually have radiotherapy to the breast after surgery. 

If you have a new breast shape made (breast reconstruction) you usually have it after the radiotherapy has finished. 

You might also have hormone therapy if your cancer cells have hormone receptors. Or you might have more chemotherapy.

Surgery as a first treatment

You usually have the whole breast removed (a mastectomy). Your surgeon will also remove some of the lymph nodes under the arm to check them for cancer cells. 

After the surgery you have radiotherapy to the breast.

You might then have surgery to create a new breast shape (breast reconstruction). 

You might have treatment with chemotherapy for a few months. 

If your cancer cells have receptors for a protein called HER2 you might have a targeted cancer drug called trastuzumab (Herceptin) as well as chemotherapy. You have this for a year.

If your cancer cells have hormone receptors you might then have hormone therapy for at least 5 years.

Inflammatory breast cancer

Some stage 3 cancers are a type called inflammatory breast cancers. The treatment is slightly different than for other stage 3 breast cancers. 

Other stages

Last reviewed: 
04 Oct 2017
  • TNM Classification of Malignant Tumours (7th edition)
    International Union Against Cancer   
    LH Sobin, MK Gospodarowicz, CH Wittekind
    John Wiley and Sons, 2009

  • AJCC Cancer Staging Manual (7th edition)
    American Joint Committee on Cancer
    Springer, 2010

  • Early and locally advanced breast cancer: diagnosis and treatment
    National Institute for Health and Care Excellence, 2009 (updated March 2017)

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