Medications Used to Treat Breast Cancer

If chemotherapy is part of a woman's treatment plan, she will soon be challenged to understand what medications are available and what they can do for and to her.

Chemotherapy is the use of chemical agents to treat cancer. These chemicals can kill cancer cells or prevent them from making new cancer cells. Many times these drugs are used in combination with one another to maximize their effectiveness. That means a woman might be given two or three at a time.

What kind of medication is given as a part of chemotherapy depends on:

the type of cancer
where it is located
how advanced it is (the stage)
the woman's health profile

Take, for example, women with HER2-positive breast cancer, meaning the cancer cells test positive for a protein known as human epidermal growth factor receptor-2 (or, HER2), which promotes the growth of cancer cells. Women with this type of cancer are treated with an anti-cancer drug — the monoclonal antibody trastuzumab — that fights only this type of cancer cell.

How Chemotherapy Is Used

Chemotherapy can be used in several different ways:

It might be used after surgery or radiation to prevent a return of cancer and kill off any cells that might remain. This is called adjuvant therapy. In this case, an oncologist will recommend chemotherapy as an additional measure even though other procedures appear to have removed or destroyed all the cancerous tissues.
Chemotherapy might be used as a first step in shrinking a tumor so that it can be surgically removed. This is called neo-adjuvant therapy. This approach could allow a woman to have a lumpectomy (removal of a tumor) instead of a mastectomy (removal of a breast).
The treatment might be prescribed to fight cancer that has metastasized, or spread, to other parts of the body.

Chemotherapy drugs are given intravenously or by mouth. They are given on schedules called “cycles” that involve having a break of a few weeks after each dose. Treatment can last for months, and the exact treatment schedule depends on the drugs involved and how the woman's body responds to the treatment.

Chemotherapy treatment might be systemic, which means it will affect the entire body, or local, meaning it is applied and directed toward a certain location. However, most chemotherapy for breast cancer is systemic and affects the whole body.

Medications Used in Chemotherapy

The main chemotherapy drugs used in breast cancer treatment are doxorubicin and docetaxel, but there are many other available drugs. They include 5-fluorouracil, cyclophosphamide, epirubicin, gemcitabine, idiomycin, methotrexate and vinorelbine. This is not a complete list as there are a number of other medications that could be used for chemotherapy.

In addition to anti-cancer medications, a woman with breast cancer might be given hormone therapy, which disables hormones or prevents them from helping cancer cells to grow. Tamoxifen, anastrozole, letrozole and exemestane are hormonal therapy treatments that are often given to women to prevent their breast cancer from spreading.

Some women will be given monoclonal antibodies, which take advantage of the immune system to fight cancer cells, whereas others might be good candidates for stem cell therapy.

Whatever medication is recommended, women should make sure they understand its risks and side effects.

Other Medications That Might Be Prescribed

Other medications can be taken to help manage some of the side effects of chemotherapy, such as nausea, fatigue and mouth pain or sores. Because each woman responds differently to the drugs used in chemotherapy, it is important to tell the oncologist about unpleasant side effects so that the medical team can help in the maintenance of a good quality of life during treatment. Changes in diet, sleep pattern, physical activity and daily schedule also might lessen the strength or impact of side effects.

Clinical Trials for Breast Cancer Treatment

New drugs and combinations of drugs are being tested constantly to try to find more effective ways to defeat breast cancer. As a first step, most oncologists will recommend a course of treatment that has been shown to be successful for the majority of women with a specific type of cancer. Women with a rare breast cancer or who have already tried the standard treatment without success might be candidates for a clinical trial. Doctors can recommend an appropriate clinical trial, or you can do your own research online.

Before enrolling, make sure you understand all the details of the trial, such as what medications you are likely to take and how long you will be required to participate.

FOR MORE INFORMATION: To research clinical trials on breast cancer, go to www.clinicaltrials.gov, a Web site provided by the U.S. National Institutes of Health.

SOURCES: American Cancer Society (www.cancer.org); National Cancer Institute (www.cancer.gov)

Written by Madeline Roberts Vann, MPH

Reviewed by Susan L. Luedke, MD

St. Louis Cancer & Breast Institute

St. Louis University Medical Center

Last updated September 2008