Metastatic breast cancer

What is it?

Metastatic breast cancer, also called secondary, advanced or stage 4 breast cancer, happens when cancer cells leave the breast and travel through the blood or lymph system.^2,1 They form new tumours elsewhere, most often in the bones, lungs, brain or liver.² The new tumours are still breast cancer: cancer that has spread to a bone is treated as breast cancer, not bone cancer.²

About 20 to 30 in every 100 women diagnosed with early breast cancer later get metastatic breast cancer.² It can come months, years or even decades after the first treatment.² In the United States, about 5 or 6 in every 100 women with newly found breast cancer already have it when they are diagnosed.²

The first signs

The signs depend on where the cancer has spread, and some people have none.²

• bone pain, or bones that break easily;²
• shortness of breath, if it is in the lungs;²
• yellow skin or eyes, or a swollen belly, if it is in the liver;²
• headaches, seizures, dizziness, or changes in speech or sight, if it is in the brain;²
• unusual tiredness.²

Other conditions can cause them too.²

How doctors find out

A sample of the new tumour (a biopsy) confirms that it is breast cancer that has spread.² It is tested for hormone receptors and HER2, because these can be different from the first tumour, and the results guide treatment.^2,4 Blood tests check how your liver and other organs work.² Scans show where the cancer is: CT, a bone scan (one injection, then a painless scan of the whole body), MRI or X-rays.^2,3 Blood tests for tumour markers can later show how well treatment works.³ A cancer specialist (oncologist) usually leads your care.³

Current treatment

Hormone, targeted or chemotherapy, by tumour typeSource: NCI

Will it get worse?

Treatment aims to stop or slow the cancer and to ease symptoms.^5,2 Some people live for years with the cancer well controlled, and many lead a normal life for several years.^2,5 Over time a medicine can stop working; then your team changes the treatment.² Palliative care, to manage symptoms and support you and your family, can be given at any time, alongside other treatment.⁴

Medicines: what helps, and what to watch for

The medicines depend on the type of cancer.^6,2 Hormone therapy lowers hormone levels or blocks them from reaching the cancer: for example letrozole, anastrozole, tamoxifen or fulvestrant.^5,7,8 It is often combined with a targeted medicine such as palbociclib, ribociclib or abemaciclib.⁷ HER2-positive cancer is treated with targeted medicines such as trastuzumab or pertuzumab.⁷ People with a BRCA gene change may get targeted therapy drugs.^7,4 Chemotherapy is also used, and for triple-negative cancer it is combined with immunotherapy.² If your cancer has spread to the bone, you may be given bisphosphonates to lower a high level of calcium in your blood.³

Good to know:

• Targeted medicines often cause diarrhoea and liver problems, and sometimes mouth sores or changes to hair and nails;⁷

Exercise and therapy help too

Tiredness is one of the most common symptoms.¹ Most cancer pain can be well controlled, and your palliative care team can advise you.^1,5

Radiotherapy and surgery, for some people

Radiotherapy can shrink tumours that cause pain or other symptoms.² Surgery is used for some people, for example to remove a tumour where the cancer has spread, to repair a bone, or to drain fluid that has built up.² Radiotherapy can ease pain and other symptoms. Cancer that has spread can be treated but not cured.^2,3

Work and family

Work and money can be big worries after a cancer diagnosis, and your treatment team may be able to tell you about sources of practical support.¹ Explain what is happening to children in a way that fits their age: children who are not told can become scared and confused.¹ Help and support are available for partners.¹ For many people the uncertainty is the hardest part.¹ If low thoughts affect your day-to-day life and do not go away within a few weeks or keep coming back, you may be depressed.¹

Is there a cure?

Metastatic breast cancer can be treated but usually not cured.^3,5 Treatment aims to keep it under control, ease symptoms and help you live longer.^5,2 Clinical trials are testing new treatments and new combinations, and you may be able to join one.⁵

Sources

1. Breast Cancer Now (charity): Living with metastatic breast cancer
2. NCI: Metastatic Breast Cancer
3. NHS (Gateshead Health NHS Foundation Trust): Secondary breast cancer
4. NCI: Breast Cancer Treatment by Stage
5. NHS: Breast cancer in women – Treatment
6. NHS: Chemotherapy – Side effects
7. NCI: Targeted Therapy for Breast Cancer
8. NCI: Hormone Therapy for Breast Cancer

read on 2026-11-11