Treatments for metastatic breast cancer

Metastatic breast cancer is cancer that has spread to other parts of the body. Cancer that has spread at the time of diagnosis is stage 4 breast cancer. Metastatic breast cancer can also mean cancer that has come back (recurred) after it has been treated.

Your healthcare team will suggest treatments based on your needs and work with you to develop a treatment plan.

The treatments offered for metastatic breast cancer depend on:

• the hormone receptor status of the cancer

• the HER2 status of the cancer
• any other genetic changes to the cancer cells
• the type and number of treatments you have had for breast cancer, including treatments for metastatic disease
• where the cancer has spread
• if the cancer is causing any symptoms
• your overall health
• any medical problems you have
• your lifestyle and what you prefer or want

Hormone therapy is offered for hormone receptor–positive breast cancer that has spread to the bones and soft tissues, such as muscles or fat. It is also given when the cancer has spread to internal organs, such as the liver, lungs or brain, but it isn't causing any symptoms.

Metastatic breast cancer is treated with an aromatase inhibitor such as:

• letrozole (Femara)
• anastrozole (Arimidex)
• exemestane (Aromasin)

If you are premenopausal you will be given a gonadotropin-releasing hormone (GnRH) agonist along with an aromatase inhibitor.

If you have been taking an aromatase inhibitor and the cancer has spread, your healthcare team will switch you to a different aromatase inhibitor.

Tamoxifen may be offered if you can't take aromatase inhibitors or if you have severe side effects from them.

Find out more about hormone therapy for breast cancer.

Chemotherapy is given for metastatic, hormone receptor–negative breast cancer. It is also offered for hormone receptor–positive breast cancer that has spread to internal organs and is causing symptoms.

There is no standard drug or drug combination for metastatic breast cancer. Chemotherapy is given as long as the cancer responds to it and the side effects do not cause problems. Once the cancer no longer responds to the treatment, a different drug or treatment may be offered.

Chemotherapy drugs are often used alone to treat metastatic breast cancer. This is because a single drug causes fewer side effects than a combination of drugs. Chemotherapy is given as long as the side effects do not cause problems and the cancer does not grow.

The following drugs may be used (usually as a single drug but sometimes combined with one another):

• anthracycline drugs such as doxorubicin, epirubicin, or pegylated liposomal doxorubicin
• taxane drugs such as paclitaxel, docetaxel, or nab-paclitaxel
• platinum drugs such as carboplatin or cisplatin
• gemcitabine
• vinorelbine
• cyclophosphamide
• capecitabine
• fluorouracil (also called 5-fluorouracil or 5-FU)

Find out more about chemotherapy for breast cancer.

Targeted therapy for metastatic breast cancer is often given in combination with chemotherapy or hormone therapy. The targeted therapy treatment offered to you by your healthcare team will be based on any targeted therapy drugs you have already had, any other treatments you have had, the number of treatments you have had, and the hormone receptor status and HER2 status of the cancer.

Metastatic breast cancer that is hormone-receptor positive and HER2 positive may be treated with the following targeted therapy drugs:

• trastuzumab (Herceptin and biosimilars)

• pertuzumab (Perjeta)

• trastuzumab and pertuzumab combination (Phesgo)
• trastuzumab emtansine (Kadcyla or T-DM1)

• trastuzumab deruxtecan (Enhertu)

• lapatinib (Tykerb)
• palbociclib (Ibrance)
• neratinib (Nerlynx)
• tucatinib (Tukysa)

Metastatic breast cancer that is hormone-receptor positive and HER2 negative may be treated with the following targeted therapy drugs:

• everolimus (Afinitor)
• alpelisib (Piqray)
• ribociclib (Kisqali)
• abemaciclib (Verzenio)

Metastatic breast cancer that is HER2 negative and has BRCA gene mutations may be treated with the following targeted therapy drugs:

• olaparib (Lynparza)

• talazoparib (Talzenna)

Find out more about targeted therapy for breast cancer.

External radiation therapy may be used to relieve pain, control the symptoms or prevent future symptoms of metastatic breast cancer. It is used to treat breast cancer that has spread to:

• lymph nodes around the breast, under the arms or around the collarbone

• the bones (bone metastases)

• the brain (brain metastases)
• the lungs (lung metastases) – to treat coughing or breathing problems

It may also be used to treat cancer that has come back in the breast. You may not be able to have radiation therapy if it has already been used to treat some areas.

Find out more about radiation therapy for breast cancer.

Surgery is rarely done to remove the tumour in the breast when the cancer has spread to other parts of the body.

Surgery may be used to:

• remove a single metastasis from a lung or the liver

• remove a metastasis from the brain (in rare cases)

• treat a broken bone or spinal cord compression if the cancer has spread to the bones

Find out more about surgery for breast cancer.

Many clinical trials in Canada are open to people with breast cancer. Clinical trials look at new ways to prevent, find and treat cancer. Find out more about clinical trials.

You may want to consider a type of care to make you feel better without treating the cancer itself. This may be because the cancer treatments don't work anymore, they aren't likely to improve your condition or they may cause side effects that are hard to cope with. There may also be other reasons why you can’t have or don't want cancer treatment.

Talk to your healthcare team. They can help you choose care and treatment for advanced cancer.