How Is Breast Cancer Treated?
Treatment for advanced or metastatic breast cancer may include a combination of approaches, both local and systemic. Local treatments are those which focus on treating the tumor in a specific area of the body, while systemic treatments go throughout the body to treat cancer cells.
How treatment is chosen
The type of treatment that is used is tailored to the individual and is chosen 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
The medical care is often provided by a team of doctors, nurses, and other healthcare professionals, which 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 treatment
Currently, there are six different standard types of treatment that may be used for breast cancer1:
In addition, new treatments are being studied in clinical trials. Patients should talk with their doctor about whether clinical trials are an option for their specific type of cancer.
Surgery is a form of local therapy. There are a variety of surgical procedures that may be used to treat breast cancer, including 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 women 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 research studies have found that removing the primary tumor can potentially improve survival while other studies have found little benefit, and surgery for metastatic breast cancer is still controversial. Women with metastatic breast cancer should discuss their options with their doctor to determine the best treatment options for them.3,4
A type of local therapy, radiation therapy 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 after breast-conserving surgery (such as a lumpectomy), after mastectomy, to treat breast cancer that has spread to the lymph nodes under the arm, or to shrink tumors and improve the symptoms of metastatic breast cancer.5,6
Chemotherapy is a systemic treatment that uses medications to treat cancer cells. Chemotherapy may be used as an adjuvant (after primary therapy) treatment in early breast cancers to reduce the risk of recurrence. Chemotherapy may also be used before surgery in certain cases to reduce the size of a tumor. In advanced or metastatic breast cancer, chemotherapy may be the primary treatment, and it may be used in combination with certain targeted therapies. For metastatic breast cancer, sequential single agents are usually recommended. This method uses one chemotherapy drug at a time, one after another, and the drug is changed to another when the breast cancer no longer responds or begins growing, or the patient can no longer tolerate the specific drug.7,8
Hormone therapy is a systemic treatment used to treat breast cancers that are hormone receptor-positive (HR+). HR+ breast cancers have receptors on the surface of their cells which 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, causing it to grow and spread faster. Hormone therapy aims to block the hormones from attaching or prevent the body from producing hormones to stop or slow the growth of breast cancer.9
Another form of systemic treatment, targeted therapy stops or slows breast cancer by interfering with specific areas of cancer cells that are involved in the cancer cell’s growth processes. There are several types of targeted therapy that are used in treating advanced breast cancer, including10,11:
- HER2-targeting agents
- CDK4/6 inhibitors
- PARP inhibitors
- mTOR inhibitors
- PI3K inhibitors
- Antibody-drug conjugates
Immunotherapy is a type of systemic treatment (treating the whole body) that aims to boost the individual’s own immune system to fight cancer. Immunotherapies are a type of biologic therapy, as they are made from substances produced from organisms that are alive.12 There are several types of immunotherapy that are currently being studied or are approved for the treatment of advanced breast cancer, including12:
- Monoclonal antibodies
- Adoptive cell transfer
Tissue-agnostic therapy is a type of treatment that treats various forms of cancer as long as the cancer has a specific molecular change or biomarker that is targeted by the treatment. 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,” which 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 FDA and others are currently being studied. Tissue-agnostic therapies include certain forms of targeted therapy and immunotherapy.
In addition to the active treatments described above to treat advanced or metastatic breast cancer, palliative care can be used alongside other treatments to ease the patient’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 patients throughout their treatment journey.14