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Stage 4

The stage of a cancer tells you how big it is and whether it has spread. It helps your doctor decide which treatment you need.

Stage 4 breast cancer has spread to another part of the body. It is also called advanced cancer or secondary breast cancer. The aim of treatment is to control the cancer and any symptoms. Treatment depends on a number of factors.

Stage 4 breast cancer means that the cancer has spread to other parts of the body.

It is also called secondary breast cancer, advanced cancer, or metastatic breast cancer.

The stage of a cancer tells you how big it is and how far it has spread. It helps your doctor decide which treatment you need.

In stage 4 breast cancer:

  • the tumour can be any size
  • the lymph nodes may or may not contain cancer cells
  • the cancer has spread (metastasised) to other parts of the body such as the bones, lungs, liver or brain
Diagram showing M stages breast

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 4 breast cancer is the same as:

  • Any T Any N M1


Your specialist will take a number of different factors into account when deciding which treatment is best for you, including:

  • which part of your body the cancer has spread to
  • the treatment you have already had
  • your general health
  • whether you have had your menopause
  • whether the cancer is growing slowly or more quickly
  • whether the cancer cells have receptors for particular types of drug treatment

Secondary breast cancer may respond to several types of treatment. Doctors try to start with treatment that has as few side effects as possible.

Remember that treatment can often keep secondary breast cancer under control for many months or years.

Types of treatment

Hormone therapy

Hormone therapy is a common treatment for secondary breast cancer. It can often shrink and control the cancer wherever it is in the body. It works well if the cancer cells have particular proteins called hormone receptors.

If one hormone therapy stops working so well, another might then help.


Your specialist might suggest chemotherapy if your cancer doesn't have hormone receptors or has spread to the liver or lungs.

Targeted drugs

You might have treatment with a targeted cancer drug such as the monoclonal antibody trastuzumab (Herceptin). Herceptin targets and blocks a protein that stimulates breast cancer cells to grow and multiply. It only works if your breast cancer cells make too much of a protein called HER2.

You may have a type of targeted drug called a cancer growth blocker. They block the proteins which tell the cell to grow and divide. These can become overactive when there are too many hormone receptors.

An example of this is a drug called palbociclib. It can help to control the growth of breast cancer cells and slow it down. This is for secondary and locally advanced breast cancers that are oestrogen positive and HER2 negative.


You might have radiotherapy if the cancer has spread to:

  • the bones
  • the brain
  • the skin near the breast or on the mastectomy scar

Bone strengthening treatment

Another treatment you may have if your cancer has spread to the bones is bone strengthening therapy. This includes a group of drugs called bisphosphonates and a targeted drug called denosumab. This treatment may also help to reduce pain. 


Surgery is not usually an option for treating secondary breast cancer. In some situations surgery can help to relieve symptoms.

Treating symptoms

Your doctor or nurse can prescribe medicines to control symptoms that the cancer causes. The symptoms will depend on where the cancer has spread to. They might include a cough, constipation, sickness, or high blood calcium levels, for example.

Making decisions about treatment

Deciding about treatment can be difficult. Treatments can help to reduce symptoms and might make you feel better. But they also have side effects that can make you feel unwell for a while. Find out about making decisions when you have secondary breast cancer.

More information about secondary breast cancer

Information can help you to understand your situation. 

Last reviewed: 
14 Jul 2020
Next review due: 
14 Jul 2023
  • AJCC Cancer Staging Manual (8th edition)

    American Joint Committee on Cancer

    Springer, 2017

  • Advanced breast cancer: diagnosis and treatment
    National Institute for Health and Care Excellence, 2009 (updated August 2017)

  • 4th ESO–ESMO International Consensus Guidelines for 

    Advanced Breast Cancer (ABC 4)

    F. Cardoso and others

    Annals of Oncology, 2018. Volume 29, Pages 1634–1657, 2018

  • TNM Classification of Malignant Tumours (8th edition)
    Union for International Cancer Control
    J Brierley, M Gospodarowicz and C Wittekind   
    Wiley Blackwell, 2017