Chemotherapy & Other Systemic Therapies for Breast Cancer

Chemotherapy drugs destroy cancer cells throughout the body. These medications may be used before surgery to shrink tumors, or after surgery to reduce the chance of a recurrence. Sometimes chemotherapy is given if the cancer has spread throughout the body.

Using chemotherapy before surgery to help shrink breast cancer tumors may enable a woman to have a lumpectomy, in which the tumor and a border of healthy surrounding tissue are removed, instead of a mastectomy.

Giving chemotherapy after surgery helps destroy any remaining cancer cells.

Women whose cancer has spread to other organs, such as the liver or lungs, may benefit from chemotherapy alone or in combination with targeted drugs, which are designed to destroy cancer cells while sparing healthy tissue.

Doctors often use a combination of chemotherapy drugs to manage breast cancer. These medications may be given through a vein with intravenous (IV) infusion or by mouth. The treatment schedule varies depending on your breast cancer type.

Generally, IV drugs are administered for several hours at a time every two to three weeks. Giving the treatment in cycles allows the body to recover between treatment sessions. People may repeat this treatment cycle several times over a period of three to six months.

Hormone therapies are often a treatment option for women whose breast tumors are estrogen or progesterone receptor positive.

Doctors usually prescribe them after surgery and radiation therapy to eliminate any remaining cancer cells, help prevent cancer from returning, and decrease the chance of new tumors developing in the same as well as the opposite breast. Sometimes these therapies are given before surgery to shrink tumors.

Selective Estrogen Receptor Modulators

Selective estrogen receptor modulators block the potentially harmful effects of the hormone estrogen in the breasts but allow it to function in other areas where it has a beneficial effect, such as the bones.

One of the most commonly used hormone therapies of this type is tamoxifen. Doctors may use it to prevent cancer from returning after surgery. It can also be used to treat women with advanced breast cancer.

Tamoxifen is taken daily by mouth. Women with early breast cancer may take the drug for as long as 5 to 10 years.

Estrogen Receptor Antagonists

The estrogen receptor antagonist fulvestrant binds to estrogen receptors on the surface of tumor cells, changing their shape. This prevents them from working well and reduces the number of tumor cells.

Doctors may use fulvestrant in postmenopausal women with advanced breast cancer that is hormone receptor positive, has spread, and does not respond to tamoxifen. Fulvestrant is given through two injections into the muscle once every two weeks. It is then given monthly.

Aromatase Inhibitors

Aromatase inhibitors block the enzyme aromatase. This helps prevent the body from producing estrogen. These hormone therapies—letrozole is one example—may work in postmenopausal women with breast cancer by blocking the small amount of estrogen that their bodies make.

Aromatase inhibitors are taken daily by mouth after other treatment is complete. Women may take these drugs for up to five years. They may also switch to an aromatase inhibitor after taking tamoxifen for five years to help prevent a recurrence.

Cyclin-Dependent Kinase Inhibitors

Cyclin-dependent kinase inhibitors called CDK 4/6 inhibitors can block the cycle of cancer cells. These include palbociclib, ribociclib, and abemaciclib. In women with advanced hormone receptor–positive breast cancer, CDK 4/6 inhibitors may improve the efficacy of conventional hormone therapies.

Ovarian Function Suppressors

Doctors may use hormone therapies to suppress ovarian function in women who are premenopausal. The ovaries produce estrogen, which can fuel breast cancer growth. Medications called luteinizing hormone–releasing hormone (LH-RH) agonists block a hormone that tells the ovaries to produce estrogen.

Targeted drugs pinpoint and destroy the cancerous cells while sparing healthy tissue. They may be used alone or are sometimes combined with chemotherapy or hormone therapy.

Monoclonal Antibodies

Antibodies are immune system proteins that recognize harmful substances as foreign to the body and help remove them. Monoclonal antibodies are drugs that bind to receptors or proteins on breast cancer cells. The drug trastuzumab, for instance, binds to human epidermal growth factor receptor-2 (HER2), preventing tumor cells from receiving signals that tell them to grow and multiply.

In women with early breast cancer, trastuzumab may be given through a vein with IV infusion every three weeks for one year.

To more effectively treat women with advanced breast cancer, doctors may prescribe trastuzumab with another monoclonal antibody or chemotherapy drug. Doctors may also use this combination of medications before surgery to manage early breast cancer.

Tyrosine Kinase Inhibitors

Tyrosine kinase inhibitors block enzymes that tell cancer cells to grow. Tyrosine kinase inhibitors such as lapatinib, neratinib, and tucatinib, target HER2 enzymes. They are taken daily by mouth. It is usually given to women who have advanced HER2-positive breast cancer that does not respond to monoclonal antibody therapies combined with chemotherapy. Doctors may also combine these targeted medicines with a monoclonal antibody or add it to other drugs to make treatment more effective.

Immunotherapy

Immunotherapy is a type of treatment that blocks the cancer-protecting shields such as PD-L1 and enables the patient’s immune system to kill tumors. These treatments include medications such as pembrolizumab and atezolizumab.

Doctors may give immunotherapy in combination with chemotherapy to women or men who have triple-negative breast cancer that has spread.

Immunotherapy is taken by IV infusion.

Breast cancer drugs and hormone therapies may have many side effects. Chemotherapy can cause nausea, infections due to low blood counts, mouth sores, and fatigue. Hormone therapies can cause hot flashes and night sweats. Some targeted drugs can result in nausea, fatigue, diarrhea, and rash.

Our doctors can help you manage these side effects by changing the dose, prescribing other medications, or referring you to NYU Langone’s integrative health services.

Perlmutter Cancer Center offers clinical trials evaluating new medications for estrogen receptor– and progesterone receptor–positive cancers, HER2-positive breast cancer, and triple-negative breast cancer, among others. We are evaluating the use of medications by women before and after surgery.

Women who are found to have genetic mutations, such as BRCA1 or BRCA2, are also participating in studies.

You and your doctor can discuss whether a clinical trial is right for you.