Each breast cancer subtype has a unique set of features that drive cancer growth, division and multiplication. Therefore, each type of breast cancer is not treated the same. Common treatment options include surgery, chemotherapy radiation or systemic therapies.

Surgeries to remove breast cancer include breast-conserving surgery, which removes the cancer as well as some surrounding normal tissue, or a mastectomy, in which the entire breast, including tissue, is removed. On the other hand, surgery to remove nearby lymph nodes includes sentinel lymph node biopsy, where a dye is injected in order to remove only the lymph nodes under the arm that have taken the dye, or an axillary lymph node dissection, where many lymph nodes are removed from the underarm.

Depending on the stage of the disease, radiation can be used after breast-conserving surgery, after a mastectomy or if the cancer has spread to other parts of the body. Similarly, chemotherapy may be recommended before or after surgery, and to treat metastatic disease.

Because some types of breast cancer are affected by hormones, treatment to stop such hormones from attaching to proteins that helps the cancer grow, hormone therapy may be used. This type of therapy is typically administered after surgery; however, sometimes it is started prior to the procedure. It can also be used to treat breast cancer that has recurred or metastasized.

Targeted therapy is used for certain types and/or stages of breast cancer. For those with HER2-positive breast cancer, targeted therapies include antibody-drug conjugates, kinase inhibitors and monoclonal antibodies. For those with hormone receptor-positive breast cancer, the use of CDK4/6 inhibitors, mTOR inhibitors and PI3K inhibitors are all considered. For those with triple-negative breast cancer, antibody-drug conjugates in combination with chemotherapy would be considered. Individuals who test positive for the BRCA mutation can also be treated with PARP inhibitors.

In addition, immunotherapy, such as immune checkpoint inhibitors, maty be used. For example, it can be used in combination with chemotherapy to treat those with triple-negative breast cancer, either before or after surgery, to treat breast cancer recurrence or disease that has spread to other parts of the body.