Treating metastatic breast cancer may involve chemotherapy, hormone therapy, targeted drugs, or immunotherapy. These treatments can target cancer that has spread to multiple parts of the body.

Metastatic breast cancer, or stage 4 breast cancer, occurs when cancer spreads beyond the breasts and the surrounding lymph nodes. Doctors may use one or more systemic treatments, which affect the whole body, to treat all the cancerous cells at once.

In some cases, doctors may also use localized treatments, such as surgery and radiation, to target cancer in one location. However, this is unlikely to remove all the cancerous cells in advanced cases.

Read on to learn more about the process of treating metastatic breast cancer.

A health worker and metastatic breast cancer patient in hospital, talking while the patient receives chemotherapy.Share on Pinterest
simon2579/Getty Images

Currently, experts consider metastatic breast cancer to be incurable, which means treatment cannot remove or destroy all the cancer. However, it is treatable.

The goal of treatment may be to shrink tumors, improve symptoms, or lengthen a person’s life. The primary treatments for metastatic breast cancer include:

  • hormone therapy
  • chemotherapy
  • targeted drugs
  • immunotherapy

Treatments may vary depending on the type of breast cancer. In some cases, doctors may also recommend surgery or radiation therapy to target tumors in specific areas as part of palliative care.

Some breast cancers have hormone receptors that respond to estrogen or progesterone levels in the body. In these cases, doctors may recommend drugs that stop these hormones from attaching to the receptors. This can prevent the tumors from growing or spreading.

Hormone therapy involves drugs such as aromatase inhibitors, tamoxifen, or cyclin-dependent kinase inhibitor therapy. The type of therapy a doctor recommends may depend on whether a person has gone through menopause.

Hormone therapy is not an option for people with hormone receptor-negative breast cancer.


Hormone therapy may prevent cancer cells from growing, shrink tumors, or slow the growth of metastatic hormone receptor-positive breast cancer.

Side effects

The side effects of hormone therapy vary depending on the type of drug treatment a person receives. However, all types of hormone therapy for cancer can cause some side effects, such as:

  • hot flashes
  • night sweats
  • vaginal dryness
  • disruption of the menstrual cycle in people who have not entered menopause

Chemotherapy involves the use of drugs that destroy cancer cells. People may take chemotherapy drugs orally or receive them through an IV line. Possible chemotherapy drugs for metastatic breast cancer include:

  • taxanes
  • ixabepilone
  • eribulin
  • anthracyclines
  • gemcitabine
  • platinum chemotherapy, such as cisplatin or carboplatin
  • vinorelbine
  • antibody drug conjugates
  • capecitabine


Doctors may recommend chemotherapy as a treatment option because it can destroy cancer cells or damage them as much as possible.

Side effects

Common side effects of chemotherapy include:

  • hair loss
  • fatigue
  • loss of appetite
  • weight changes
  • nausea
  • vomiting
  • diarrhea
  • nail changes
  • mouth sores
  • hot flashes
  • vaginal dryness
  • nerve damage
  • increased risk of infection

Targeted therapy uses drugs to target a specific part of cancer cells, such as a certain protein that allows cancer cells to grow rapidly.

The drugs that doctors may prescribe for metastatic breast cancer include:

  • trastuzumab
  • lapatinib
  • pertuzumab
  • mTOR inhibitors
  • antibody-drug conjugate therapy using ado-trastuzumab emtansine
  • cyclin-dependent kinase inhibitor therapy, which doctors may combine with hormone therapy
  • tucatinib
  • PARP inhibitors such as olaparib or talazoparib


Compared with other treatments, such as chemotherapy, targeted drugs may be less likely to damage healthy, noncancerous cells.

Additionally, some types of targeted drugs work similarly to the antibodies the immune system naturally creates.

Side effects

The side effects of targeted therapy vary for each type of drug but may include:

  • fatigue
  • mouth sores
  • rash
  • nausea and vomiting
  • diarrhea
  • low blood counts
  • loss of appetite

Immunotherapy uses drugs to stimulate the immune system so that it can fight cancer cells. This may involve taking PD-1 or PD-L1 inhibitors.


Immunotherapy supports the immune system to:

  • prevent or slow down growth of cancer cells
  • prevent cancer cells from spreading
  • better destroy cancer cells

Side effects

The possible side effects of immunotherapy include:

  • fatigue
  • nausea
  • cough
  • loss of appetite
  • constipation
  • diarrhea
  • skin rash
  • infusion reaction to the drug
  • autoimmune reactions

Doctors do not often recommend surgery for metastatic breast cancer, as it is unlikely to remove all the cancerous cells, especially if the cancer has spread to multiple places. However, they may suggest surgery if a person has:

  • De novo metastatic breast cancer: This refers to cases in which people receive a diagnosis at stage 4. Sometimes, a doctor may suggest surgery to remove the primary tumor in the breast, even if it has already spread elsewhere, as this may help extend a person’s life.
  • Liver metastases: Doctors may consider surgery to remove liver metastases if the tumors are hormone receptor-positive, responded to chemotherapy before surgery, and did not grow in the time between diagnosis and surgery.
  • Small, isolated tumors: Surgery is typically not effective for these types of tumors, but if a systemic treatment is working to control them, a doctor may suggest a procedure known as cryotherapy. This involves directing a probe under the skin to find small tumors. Once the probe is in position, it releases gas that freezes and kills the cancerous cells.

In some cases, doctors may also recommend surgery or radiation therapy if the cancer:

  • is blocking blood vessels or airways
  • is causing internal bleeding
  • may cause a bone to break
  • is pressing on a nerve or causing other complications

Treatment for metastatic breast cancer may help manage the disease for years. However, the outcome will vary case by case. The location and type of cancer, as well as how it responds to treatment, will affect the outlook.

If one treatment is not effective or stops working, a doctor may suggest other options. Using a combination of treatments may lead to a better outcome for metastatic cancer.

When thinking about treatment options, a person may want to ask their doctor questions such as:

  • Do I need testing to check the hormone receptor status of the cancer?
  • Would genetic testing help determine the best treatment?
  • How will treatment affect my everyday life?
  • What are the benefits and disadvantages of each option?
  • How can I deal with the side effects?
  • How do you know when the treatments are working?
  • What happens if it does not work?
  • What if I decide not to have treatment?
  • Are there any clinical trials that may be worth joining?

Metastatic breast cancer is cancer that has spread outside the breast area to other parts of the body. Treatment may involve hormone therapy, chemotherapy, targeted drug therapy, or immunotherapy. Occasionally, treatment may include surgery or radiation.

Treatment cannot cure metastatic breast cancer, but it may help improve quality of life and survival time. A combination of treatments may provide the best outcome.

If a person experiences any unusual or severe side effects, they should inform their healthcare team right away. People can also talk with a doctor about how to manage side effects such as nausea.