How Is Breast Cancer Treated?

Treatment for advanced or metastatic breast cancer may include a combination of approaches. Local treatments focus on treating the tumor in a specific area of the body. Systemic treatments work throughout the body to treat cancer cells.

How treatment is chosen

The type of treatment used is tailored to each person and based on several factors, including:

• The stage or extent of the cancer
• The age and menopausal status of the woman
• Whether the breast cancer is hormone receptor-positive or negative (HR+/-)
• Whether the breast cancer is human epidermal growth factor receptor 2 positive or negative (HER2+/-)
• The general health of the woman
• Possible side effects of the treatment

Metastatic breast cancer treatment team

Medical care is often provided by a team of doctors, nurses, and other healthcare professionals. This may include:

• Breast surgeon
• Radiation oncologist
• Medical oncologist
• Plastic or reconstructive surgeon
• Oncology nurse
• Palliative care doctor
• Physical therapist
• Oncology social worker
• Counselor or therapist

Types of metastatic breast cancer treatment

There are 6 different types of standard treatment that may be used for breast cancer:¹

• Surgery
• Radiation therapy
• Chemotherapy
• Hormone therapy
• Targeted therapy
• Immunotherapy

New treatments are also being studied in clinical trials. Talk with your doctor about whether clinical trials are an option for your specific type of cancer.

Surgery

Surgery is a form of local therapy. There are a variety of surgical procedures used to treat breast cancer. These include surgery to the breast and surgeries to other areas of the body, such as the lymph nodes under the arm (axillary lymph nodes) and the ovaries. Surgery options to the breast include breast-conserving procedures and mastectomy, which removes the entire breast.

For people with metastatic breast cancer (cancer that has spread to other parts of the body), treatment may or may not include surgery to the primary tumor in the breast. Some studies have found that removing the primary tumor may improve survival. However, other studies have found little benefit. Surgery for metastatic breast cancer is still controversial. People with metastatic breast cancer should discuss their options with their doctor to determine the best treatment options for them.^3,4

Radiation therapy

Radiation therapy is a type of local therapy. It uses high doses of radiation to kill cancer cells in a specific area. Cancer cells multiply rapidly and are more susceptible to radiation than healthy cells. Radiation therapy may be used:^5,6

• After breast-conserving surgery (such as a lumpectomy)
• After mastectomy
• To treat breast cancer that has spread to surrounding lymph nodes or nearby tissue
• To shrink tumors and improve the symptoms of metastatic breast cancer

Chemotherapy

Chemotherapy is a systemic treatment that uses drugs to treat cancer cells. Chemotherapy may be used as an adjuvant (after primary therapy) treatment in early breast cancers to reduce the risk of the cancer coming back (recurrence). In some cases, chemotherapy may be used before surgery to reduce the size of a tumor.^7,8

In advanced or metastatic breast cancer, chemotherapy may be the primary treatment. It may be used along with certain targeted therapies or immunotherapies. For metastatic breast cancer, sequential single agents are usually recommended. This method uses 1 chemotherapy drug at a time, 1 after another. The drug is changed when the breast cancer no longer responds or begins growing, or the person can no longer tolerate the specific drug.^7,8

Hormone therapy

Hormone therapy is a systemic treatment for breast cancers that are hormone receptor-positive (HR+). HR+ breast cancers have receptors on the surface of their cells that bind to hormones in the body like estrogen and progesterone. When these hormones connect to the receptors on cancer cells, it can fuel the growth of breast cancer. This causes the cancer to grow and spread faster. Hormone therapy aims to block the hormones from attaching or prevent the body from producing hormones. This helps to stop or slow the growth of breast cancer.⁹

Targeted therapy

Targeted therapy is another type of systemic treatment. It stops or slows breast cancer by interfering with specific areas of cancer cells that are involved in the cancer cell’s growth processes, or by focusing on specific features that are unique to cancer cells. Several types of targeted therapy are used to treat certain forms of breast cancer, including:^10,11

• HER2-targeting agents
• CDK4/6 inhibitors
• PARP inhibitors
• mTOR inhibitors
• PI3K inhibitors
• AKT inhibitors
• Antibody-drug conjugates

Immunotherapy

Immunotherapy is a type of systemic treatment that aims to boost the immune system to fight cancer. Several types of immunotherapy are being studied or are approved for the treatment of certain forms of breast cancer, including:¹²

• Monoclonal antibodies
• Adoptive cell transfer

Tissue-agnostic treatment

Tissue-agnostic therapy is a type of treatment that treats various forms of cancer that have a specific molecular change or biomarker. This is different from other treatments that depend on the type of tissue or location of the cancer. Tissue-agnostic drugs are studied in clinical trials known as “basket trials.” These are clinical trials that test how well a drug works for treating multiple types of cancer within the same trial.¹³

Several tissue-agnostic treatments have been approved by the U.S. Food and Drug Administration (FDA). Others are being studied. Tissue-agnostic therapies include certain forms of targeted therapy and immunotherapy.¹³

Palliative care

Palliative care can be used alongside other treatments to ease a person's side effects or symptoms from cancer and cancer treatment. Palliative care can significantly improve a person’s quality of life while they are undergoing treatment for breast cancer. Palliative care is different than hospice care, which is given near the end of life. Instead, palliative care can aid people throughout their treatment journey.¹⁴