Metastatic breast cancer is breast cancer that has spread beyond the breast to other organs, most often to the bones, lungs, liver or brain. It’s also called stage IV or advanced breast cancer. Most often, metastatic breast cancer arises years after a person has completed treatment for early or locally advanced breast cancer. This may be called a distant recurrence.

As hard as it is to hear, metastatic breast cancer can’t be cured today. Unlike breast cancer that remains in the breast or nearby lymph nodes, medical treatments can’t get rid of all the cancer that’s spread to other parts of the body.

However, metastatic breast cancer can be treated. Treatment focuses on extending life and maintaining quality of life.

Your treatment plan is guided by many factors, including:

• The biology of the tumor (characteristics of the cancer cells)
• Where the cancer has spread
• Your symptoms
• Past breast cancer treatments
• Your overall health, age, menopausal status and other medical issues, as well as your
• Personal goals and preferences

If the cancer is hormone receptor positive, hormone therapy is the first treatment. It can include tamoxifen, aromatase inhibitors or fulvestrant. If a woman with metastatic breast cancer is premenopausal, hormone therapy almost always begins with ovarian suppression and either an aromatase inhibitor, tamoxifen or other hormone therapy drug.

Ovarian suppression lowers hormone levels in the body so the tumor can’t get the estrogen it needs to grow. This may involve surgery to remove the ovaries (called oophorectomy) or, more often, drugs (such as goserelin or leuprolide) to stop the ovaries from producing hormones.

Often a CDK4/6 inhibitor drug is used with hormone therapy. This may give people more time before the cancer spreads and increase overall survival. Sometimes, an mTOR inhibitor or PI3 kinase inhibitor may be used with hormone therapy and may give more time before the cancer spreads.

If the cancer is HER2-positive, HER2-targeted therapies are included in the treatment plan. HER2-targeted therapies include specially made antibodies, antibodies combined with chemotherapy drugs and tyrosine kinase inhibitors. HER2-targeted therapies may give more time before the cancer spreads and increase overall survival.

The HER2-targeted therapy trastuzumab deruxtecan, or Enhertu, can be used to treat metastatic breast cancers that have low, but detectable levels of HER2 expression. These are called HER2-low breast cancers. Trastuzumab deruxtecan may increase survival in some people who have HER2-low metastatic breast cancers.

Chemotherapy can be used to shrink or slow the growth of tumors or to ease symptoms of the cancer. If the initial chemotherapy regimen stops working, other drugs or combinations of drugs can be used. It’s common for people to have multiple chemotherapy regimens during the course of their treatment.

PARP inhibitor drugs, including olaparib, or Lynparza, and talazoparib, or Talzenna, are used to treat metastatic breast cancer in people who have a BRCA1 or BRCA2 inherited gene mutation. The National Comprehensive Cancer Network recommends everyone with metastatic breast cancer get BRCA genetic testing to see if a PARP inhibitor may be used for treatment.

Compared to chemotherapy alone, adding olaparib or talazoparib may give women with a BRCA inherited gene mutation and HER2-negative metastatic breast cancer more time before the cancer spreads.

For metastatic cancer, triple negative breast cancers that are PD-L1-positive, the first treatment may be the immunotherapy drug pembrolizumab, or Keytruda, in combination with chemotherapy. All metastatic triple negative breast cancers are tested to learn if they are PD-L1-positive to see whether pembrolizumab would be helpful as a first treatment.

Compared to chemotherapy alone, pembrolizumab in combination with chemotherapy may give people with metastatic PD-L1-positive triple negative breast cancer more time before the cancer spreads.

Some breast cancers have cells that express the protein Trop-2. Triple negative breast cancers tend to express Trop-2. Sacituzumab govitecan, or Trodelvy, is an FDA- approved antibody-drug conjugate used to treat metastatic triple negative breast cancers. Sacituzumab govitecan helps shrink tumors in women with metastatic triple negative breast cancers and may improve survival.

Surgery is rarely used to treat metastatic breast cancer since it does not improve survival.

Ask your health care provider about the details of the treatment recommended for your individual situation.

You’ll be checked regularly to see if your current treatment is working. Monitoring can include physical exams, imaging tests and blood tests for tumor markers. Tumors often develop resistance to drugs used to treat metastatic breast cancer, so changing therapies is common.