Treating metastases throughout the body

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If breast cancer has spread to other parts of the body, the entire body is usually treated with medication to limit tumor growth. This is known as systemic therapy. The medications used may include , chemotherapy or antibodies. Surgery or radiotherapy generally tend to be used for the treatment of individual metastases.

When treating metastatic breast cancer, different systemic treatments are typically used one after the other or in combination with each other. If tumor cells stop responding to a certain drug after a while, another drug or treatment approach can be used. This step-by-step approach is known as sequential therapy. Some metastatic tumors can also be treated with radiation, and it might be possible to surgically remove certain tumors.

All types of systemic therapy have severe side effects that can be very distressing. The side effects vary depending on the kind of treatment, but they can usually be treated effectively themselves. The treatment of side effects is part of what is known as supportive care.

How does hormone therapy work?

In women with "hormone-receptor-positive" breast cancer, the growth of the tumor is usually stimulated by the estrogen and progesterone. The growth of these hormone-sensitive tumors can be slowed down by reducing the production of in the ovaries or interfering with the effects of the . This is known as hormone therapy. It involves taking medications called anti-estrogens (e.g. tamoxifen or fulvestrant) before menopause, or medications called aromatase inhibitors after menopause. Medications known as GnRH analogues are sometimes used as well, particularly in younger women. When taken regularly, these drugs prevent the ovaries from producing sex and stimulating tumor growth.

If the tumors are hormone-sensitive, hormone therapy is typically recommended first (instead of chemotherapy).

Side effects and complications

Anti-estrogens may increase the risk of thrombosis and cause changes in the lining of the womb that can lead to bleeding. Aromatase inhibitors can cause muscle and joint problems, among other things. They can also lower bone density, which increases the risk of bone fractures.

Younger women who are having hormone therapy stop getting their periods. They can't get pregnant during this treatment. The treatment often leads to symptoms that can also happen during menopause: hot flashes, sleep problems, and dry skin and mucous membranes.

How does chemotherapy work?

Chemotherapy is treatment with drugs that inhibit cell division. These drugs are called cytostatics. Cytostatics are usually given as infusions (as a drip), but are also sometimes taken in the form of tablets. There are many different cytostatics. They can either be combined with each other or used on their own (monotherapy). Because they travel through the bloodstream, cytostatics affect the whole body and can even reach metastatic tumors that might not have been discovered yet.

The aim of chemotherapy is to slow down or stop tumor growth, or to make tumors shrink as much as possible. To treat metastatic breast cancer, different types of chemotherapy are typically used one after the other. The decision about which medications to use will be based on various factors, including how distressing the possible side effects are considered to be. Other medical conditions may play a role too when choosing the treatment.

Chemotherapy usually consists of several cycles or courses of treatment. This means that you receive the medication over several days, and then stop for a while so your body can recover. Nowadays, chemotherapy is usually given in an outpatient setting. You may need to stay at the hospital if, for example, certain body functions have to be closely monitored during the intensive part of the treatment.

Side effects and complications

Chemotherapy damages healthy body cells, too – particularly cells that divide rapidly. These include cells in the hair and mucous membranes, but also blood cells. The resulting side effects include hair loss, mouth sores, nausea and digestion problems. Damage to the blood cells can make people pale, prone to infections, short of breath, and exhausted (). They may also bleed more easily.

The severity of side effects varies from woman to woman and also depends on the drug, the dose, how the drug is used, and the number of treatment cycles.

There are effective treatments for some of the side effects. For example, anti-nausea medication can be taken before (for prevention) and during chemotherapy. Infections that arise during chemotherapy can be treated with .

Chemotherapy can affect as well. It may cause your monthly periods to stop or lead to early menopause. Whether or not a woman's menstrual cycle returns to normal after chemotherapy will depend on various factors, including her age.

What are targeted therapies?

Some medications specifically target cancer cells that have certain characteristics. If the cancer cells have the growth factor receptor HER2 on them (in other words, if they are HER2-positive), then medications can be used to block signals that promote growth. This can slow the growth of the cancer cells and shrink the metastases. Antibodies such as pertuzumab and trastuzumab are used for this purpose. The drug lapatinib is also an option here.

These medications are typically used in combination with chemotherapy.

Trastuzumab can also be used together with the drug emtansine. Trastuzumab binds to the cancer cells and prevents them from growing. Emtansine is attached to the antibody when used for this purpose. This “antibody-drug conjugate” is believed to specifically kill the cancer cells.

Another example of an antibody used in breast cancer treatment is bevacizumab. It is used to treat HER2-negative tumors, where the cells' growth-stimulating signals can't be blocked. Bevacizumab is supposed to block the supply of nutrients to the cancer cells.

Medications known as CDK4/6 inhibitors can also be used for targeted therapy. They are an option in the treatment of hormone-sensitive, HER2-negative breast cancer. CDK4/6 inhibitors are combined with hormone therapy (usually aromatase inhibitors). They are believed to inhibit the growth of the cancer cells by blocking certain proteins (enzymes).

Side effects and complications

Trastuzumab can have various negative effects, including damage to the heart. When combined with emtansine it can cause blood clotting problems, exhaustion (), nausea, vomiting and diarrhea. The possible side effects of pertuzumab include anemia, a decrease in the number of white blood cells, and diarrhea. Bevacizumab can cause high blood pressure, and bleeding in the digestive tract, and also prevent the kidneys from working properly.

The possible side effects of lapatinib include diarrhea, skin rashes and liver damage.

CDK4/6 inhibitors can lead to side effects like nausea, vomiting, diarrhea, hair loss and anemia. They may also weaken your , increasing your risk of infections.

When are surgery and radiotherapy considered?

In metastatic breast cancer, the cancer has already spread to other parts of the body. Non-surgical treatments are then the main options for keeping tumor growth under control. Breast tumors are surgically removed, if possible.

In radiotherapy – also called radiation therapy – the tumor tissue is exposed to high-energy radiation. The aim is to damage cancer cells so much that they die. In external radiotherapy, radiation is aimed at the cancer from outside the body, through the skin (percutaneously). In internal radiotherapy (brachytherapy), radioactive material is placed directly inside the tumor or very close to it.

Radiotherapy is usually the treatment of first choice if it's no longer possible to surgically remove the tumor or reduce its size. Radiotherapy can also be used to treat metastatic tumors.

Side effects and complications

Just like after any operation, the area in question might hurt. The surgery usually leaves a visible scar. The wound-healing process might take longer due to other cancer-related treatments. But wound-healing problems are rare.

One of the most common side effects of radiotherapy is tiredness. Radiation can also damage healthy tissue, particularly the skin in the treated area. The skin there may become sensitive or red, for example. But healthy cells can recover more easily than tumor cells can. So these problems usually only occur during the treatment and for some time afterwards. If lymph nodes are exposed to radiation, that increases the risk of lymphedema.

What should you know about “complementary” therapies?

Many people would like to use complementary or “alternative” treatment approaches such as herbal medication, homeopathy or because they believe it will strengthen their self-healing powers and improve their wellbeing.

In Germany, statutory health insurers don't pay for most complementary therapies because there's a lack of scientific proof that they work. If you're considering a complementary therapy, it's best to contact your health insurer beforehand to see whether they would cover the costs.

Some complementary therapies may also have adverse effects. It is important for any treatment to have a proven benefit. If you rely on a treatment that doesn't have a benefit, you may easily invest a lot of time and money in something that doesn't help.

What’s more: Contrary to popular belief, "herbal" doesn't necessarily mean "harmless." For example, mistletoe therapy, which is sometimes used in cancer treatment, can cause side effects like allergic reactions or fever.


You should always let your doctors know if you’re using any complementary medicine products or dietary supplements.

This is because some complementary medicines can influence the effectiveness of other drugs, such as anesthetics and painkillers, or increase the risk of bleeding. Complementary medicines can also alter the effect of breast cancer treatment: They may reduce its effectiveness or make the side effects worse.

Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG), Deutsche Krebsgesellschaft (DKG). Interdisziplinäre S3-Leitlinie für die Früherkennung, Diagnostik, Therapie und Nachsorge des Mammakarzinoms. AWMF-Registernr.: 032-045OL. 2021.

Deutsches Krebsforschungszentrum (DKFZ), Krebsinformationsdienst (KID). Brustkrebs: Zielgerichtete Therapien. 2016.

Deutsches Krebsforschungszentrum (DKFZ), Krebsinformationsdienst (KID). Wie läuft eine Chemotherapie ab? Häufige Fragen zur Krebsbehandlung mit Zytostatika. 2019.

Kommission Mamma der Arbeitsgemeinschaft Gynäkologische Gynäkologie (AGO), Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG), Deutsche Krebsgesellschaft (DKG). Diagnostik und Therapie von Patientinnen mit primärem und metastasiertem Brustkrebs). 2023.

National Institute for Health and Care Excellence (NICE). Advanced Breast Cancer: Diagnosis and Treatment. (NICE Clinical Guidelines; No. 81). 2017.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on January 23, 2024

Next planned update: 2027


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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