Understanding secondary breast cancer

What is secondary breast cancer?

Secondary breast cancer is when cancer cells spread from the breast to other parts of the body. Cancer that starts in the breast is called primary breast cancer.

Secondary breast cancer is also called advanced breast cancer or metastatic breast cancer. The most common places for breast cancer to spread to are the:

bones
lungs
liver
brain
skin.

This does not mean that secondary breast cancer will spread to all of these places.

Rarely, breast cancer can spread to other parts of the body, such as the bone marrow, tissue that covers the brain and spinal cord (meninges), ovaries and the lining of the abdomen (peritoneum). If you need more information about this, you can call our cancer support specialists on 0808 808 00 00.

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How does cancer spread from the breast?

For many people, primary breast cancer never comes back after treatment. But sometimes cancer cells spread to other parts of the body through the blood or the lymphatic system.

Breast cancer cells that have spread may begin to grow and form another tumour. This is called a secondary breast cancer or metastatic breast cancer.

Sometimes people recently diagnosed with primary breast cancer also have a secondary cancer. This can be found through tests and scans.

The secondary cancer is made up of breast cancer cells. Doctors treat it with the same drugs used to treat breast cancer. For example, a secondary breast cancer in the lung is treated as breast cancer, not lung cancer.

Local and regional recurrence of breast cancer

Sometimes breast cancer comes back in the treated breast or the scar. This is called a local recurrence. Sometimes breast cancer comes back in the lymph nodes in the armpit, close to the breastbone or in the lower neck. This is called a regional recurrence. This is different to secondary breast cancer.

We have more information about breast cancer recurrence.

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What is cancer?

Symptoms of secondary breast cancer

The symptoms of secondary breast cancer depend on where in the body the cancer has spread. If it has spread to the bones there might be a painful area in a bone. If it has spread to a lung it may cause breathlessness.

Some people have general symptoms, such as feeling more tired, poor appetite or feeling generally unwell for no obvious reason. Tell your doctor or nurse if you have any new symptoms. We have more information about symptoms of secondary breast cancer.

Causes of secondary breast cancer

There are no specific risk factors for secondary breast cancer. The risk factors are the same as for primary breast cancer.

Diagnosis of secondary breast cancer

You may be diagnosed with secondary breast cancer after having tests to check a new symptom. This could be through your GP or at a breast cancer follow-up clinic. Sometimes there may be no obvious symptoms and the diagnosis is made after routine follow-up tests.

Sometimes people recently diagnosed with primary breast cancer have tests that show they have secondary breast cancer. Sometimes secondary breast cancer can be the first diagnosis of breast cancer.

Your doctor and nurse will explain which tests and scans you need. This will depend on your symptoms. You will usually have some of the following tests or scans.

Blood tests
Blood tests cannot diagnose secondary breast cancer. But they may show that you need further tests. You may have blood tests to:

check how well the liver and kidneys are working

check the level of calcium in the blood

measure the number of blood cells to show how well the bone marrow is working – the bone marrow is where blood cells are made

measure tumour markers.

Tumour markers are proteins some cancers produce. The levels of them in your blood may be raised if you have cancer. But measuring them is not always reliable. Your doctor can tell you whether measuring tumour markers is helpful in your situation.
CT scan

A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the body.
Bone scan

A bone scan looks for changes in the bones. It is more sensitive than an x-ray, as it shows any abnormal areas of bone more clearly.
Bone x-rays

If you have a painful area in your bones, you may have an x-ray to check for signs of cancer. The x-ray may also show weakened areas of bone that are at a higher risk of fracture. It may not show small areas of secondary cancer. You will usually have a bone scan to confirm the diagnosis.
Chest x-ray

A chest x-ray can help to see if there is secondary breast cancer in the lungs. It can also show any build-up of fluid between the tissues on the outside of the lungs (the pleura). You will also usually have a lung CT scan. You may have a CT scan of the liver rather than an ultrasound.
Liver ultrasound

A liver ultrasound uses soundwaves to build up a picture of the liver. It is painless and only takes a few minutes.
PET-CT scan

A PET scan uses a low dose of radiation to check the activity of cells in different parts of the body.

You may have a PET scan and a CT scan together. This is called a PET-CT scan. It can give more detailed information about cancer or abnormal areas seen on other scans.
MRI scan

An MRI scan uses magnetism to build up detailed pictures of areas of the body.
Biopsy

A biopsy is when doctors remove a small piece of tissue or a sample of cells from an area of the body. This is how doctors find out whether an abnormal area or lump (tumour) is cancerous (malignant) or non-cancerous (benign).

They can see if the cells have come from a cancer that started in the breast (primary breast cancer). A secondary breast cancer is always made up of breast cancer cells.

If you have not been diagnosed with primary breast cancer before, you will need to have a biopsy. This is to confirm the diagnosis and to find out which receptors the cancer has.

Where you have the biopsy taken from depends on your scan results and symptoms. For example, you may have a biopsy taken from your lungs, liver or bone.

It is not always possible to do a biopsy. Sometimes the area is too difficult to reach. Or you may be too unwell. Your doctor will discuss this with you. If needed, they can arrange other tests instead.

It may take from a few days to a couple of weeks for the results to be ready. Waiting for test results can be a difficult time. We have more information that can help. We have more information that can help. We're also here if you need someone to talk to. You can:

Call the Macmillan Support Line for free on 0808 808 00 00.
Chat to our specialists online.

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Stages of secondary breast cancer

The stage of a cancer describes its size and if it has spread from where it started. This information helps you and your doctor make decisions about your treatment.

Doctors often stage breast cancer using a system that divides into 4 number stages. Secondary breast cancer is always stage 4. This is when the cancer has spread to other parts of the body such as the bones, liver or lungs.

Receptors for secondary breast cancer

Breast cancer cells may have receptors on the outside of the cells. Hormones, such as oestrogen can attach to the receptors and encourage the cells to grow. Some breast cancer cells have too much of a protein called human epidermal growth factor receptor 2 (HER2) on their surface.

A doctor called a pathologist tests cancer cells for receptors. These cells are taken during a biopsy or surgery. A biopsy gives doctors information about whether the secondary cancer has receptors for hormones or for HER2.

The results help you and your doctor decide on the most effective treatment for you. If you had primary breast cancer before, these results may not be the same as for the primary breast cancer. It may mean your cancer doctor suggests different treatment.

Cancer that does not have receptors for either hormones or HER2 is called triple negative breast cancer.

Hormone receptors

Breast cancers with receptors for oestrogen are called oestrogen receptor (ER) positive. Most breast cancers are ER positive. Hormonal therapy is usually used to treat ER positive breast cancer. Breast cancer cells may also have receptors for the hormone progesterone (PR). This is called PR positive breast cancer.
HER2

Some breast cancer cells have too much of a certain kind of protein (receptor) called HER2. This type of breast cancer is called HER2 positive breast cancer. Specific targeted therapy drugs are used to treat HER2 positive breast cancer.

Other tests before treatment

A pathologist can check cancer cells from your biopsy for certain gene changes. They can also check for certain proteins. These results help doctors plan your treatment.

For example, triple negative breast cancers can be checked for a protein called PD-L1. Drugs called PD-L1 or PD-1 inhibitors can then be used for this type of breast cancer.

You may be offered other tests as part of a clinical trial.

Treatment for secondary breast cancer

A team of specialists meet to talk about the best treatment for you. They are called a multidisciplinary team (MDT).

Your cancer doctor and specialist nurse will talk to you about your treatment options. Talk to them about what you prefer.

Treatments for secondary breast cancer are advancing. This means people are living with the cancer for longer. You may have single or combined treatments one after the other to keep the cancer under control. This is called lines of treatment. If a treatment stops working, you can usually try another treatment that may work for a time.

Treatments for secondary breast cancer include:

Hormonal therapies

Hormonal therapy drugs lower the level of oestrogen in the body. Or they block oestrogen from attaching to the breast cancer cells. They only work for breast cancer that is oestrogen receptor (ER) positive.
Chemotherapy

Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. The drugs are carried in the blood and can reach cancer cells anywhere in the body. You may have chemotherapy on its own or with a targeted therapy drug.

Electrochemotherapy may be used to treat skin tumours caused by secondary breast cancer. It uses chemotherapy and a small electrical current to destroy the cancer cells.
Targeted therapy

Targeted therapy interferes with the way cancer cells signal or interact with each other. This stops them from growing and dividing. There are different targeted therapy drugs and they all work in different ways.
Radiotherapy

Radiotherapy uses high-energy rays called radiation to treat cancer. You may have radiotherapy to relieve pain from secondary breast cancer in the bone. Radiotherapy can also be used to shrink secondary cancer in the brain, skin or lymph nodes.
Bone strengthening drugs

If you have secondary breast cancer that has spread to the bones, you may be given bone-strengthening drugs. These may be bisphosphonates or a targeted therapy called denosumab (Xgeva^®).

These drugs also relieve bone pain and reduce the risk of a broken bone (fracture). Your cancer doctor may prescribe them to reduce the risk of developing further problems.
Surgery

Surgery is not usually used to treat secondary breast cancer. Sometimes surgery is used to remove a small tumour in the brain or liver, or to help strengthen a weak bone.
Steroids

Steroids may be used to help control symptoms and help you to feel better.
Immunotherapy

Immunotherapy drugs may be used to treat triple negative breast cancer. They may also be used as part of a clinical trial.

We have more information about treatment for secondary breast cancer.

Controlling symptoms of secondary breast cancer

The symptoms of secondary breast cancer may improve with cancer treatment. Sometimes this works quickly and you may notice an improvement within a few days. But sometimes it may take a few weeks before you feel better.

There are also lots of other ways to control and manage symptoms. Always tell your cancer doctor or specialist nurse if you have new symptoms or if your symptoms get worse.

Sometimes you may be referred to a doctor or nurse who is an expert in treating pain and other symptoms. They are sometimes called supportive or palliative care specialists.

We have more information about controlling symptoms of secondary breast cancer.

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Living with secondary breast cancer

You will see your cancer doctor or specialist nurse regularly during your treatment. This helps make sure any problems can be managed. How often you see them will depend on your treatment plan.

You will have regular scans or x-rays to check how the cancer is responding to treatment. Contact your cancer doctor or nurse if you have any concerns or notice any new symptoms between appointments. If you are having treatment such as chemotherapy, targeted therapy or immunotherapy, you will be given a number to call if you feel unwell.

You may need treatment at different times, or have ongoing treatment. There may be long periods when the cancer is controlled, and you are getting on with day-to-day life .

You are likely to have different feelings during treatment. You may also be worried about practical issues such as work or finances. It is important to take care of yourself. This may include:

Getting enough rest
Trying to keep physically active
Eating healthily.

We have more information about well-being and coping. It is also important to get the support you need. You can get support from:

your healthcare team
partners, family or friends
support groups.

Sex life

Cancer and its treatment may affect your sex life and your fertility (ability to get pregnant or make someone pregnant). Some cancer treatments can cause specific problems such as pain during sex, vaginal dryness and problems with erections.

Your cancer doctor, specialist nurse or GP can give you advice on the best contraception for you to use. This may depend on the cancer treatments you are having. We have more information about sex and cancer.

You may get anxious between appointments. This is natural. It may help to get support from family, friends or a support organisation.

Macmillan is also here to support you. If you would like to talk, you can:

Call the Macmillan Support Line on 0808 808 00 00.
Chat to our specialists online.
Visit our secondary breast cancer forum to talk with people who have been affected by secondary breast cancer, share your experience, and ask an expert your questions.

Related pages

Finishing cancer treatment

About our information

References

Below is a sample of the sources used in our secondary breast cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

National Institute for Health and Clinical Excellence (NICE). Advanced breast cancer: diagnosis and treatment. Clinical Guideline [CG81]. Updated 2017. Available from: www.nice.org.uk/guidance/cg81 (accessed November 2021).

BMJ best practice. Metastatic breast cancer. Available from: https://bestpractice.bmj.com/topics/en-gb/718 (accessed November 2021).

Reviewers

This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Dr Rebecca Roylance, Consultant Medical Oncologist and Professor Mike Dixon, Professor of Surgery and Consultant Breast Surgeon.

Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

use plain English
explain medical words
use short sentences
use illustrations to explain text
structure the information clearly
make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.