This series of fact sheets is based on the work of the U.S. Preventive Services Task Force (USPSTF). The USPSTF systematically reviews the evidence of effectiveness of a wide range of clinical preventive services—including screening, counseling, and chemoprevention (the use of medication to prevent diseases)—to develop recommendations for preventive care in the primary care setting.
This fact sheet presents highlights of USPSTF recommendations on this topic and should not be used to make treatment or policy decisions. More detailed information on this subject is available from the USPSTF and the July 2, 2002, issue of the Annals of Internal Medicine 137:56-67.
Breast cancer chemoprevention is the use of prescription medicines, such as tamoxifen and raloxifene, to prevent breast cancer.
Breast cancer is the most common non-skin cancer in women. It is estimated that 203,500 new cases of invasive breast cancer will be diagnosed in 2002, and that 39,600 women will die from the disease. Early detection of breast cancer through mammography has reduced the number of deaths from breast cancer; another approach to reducing breast cancer deaths among women at high risk for the disease is chemoprevention.
The U.S. Preventive Services Task Force (USPSTF) recommends against the routine use of the medications tamoxifen or raloxifene for the primary prevention of breast cancer in women at low or average risk for breast cancer. For women who are not at high risk for breast cancer, the potential harms of chemoprevention may outweigh the potential benefits.
The USPSTF recommends that clinicians discuss chemoprevention with women at high risk for breast cancer and at low risk for the adverse effects of chemoprevention, informing them of the potential benefits and harms. The balance of benefits and harms may be favorable for some women at high risk for breast cancer but depends on cancer risk, risk for adverse effects of chemoprevention, and individual patient preferences.
Chemoprevention of breast cancer is not recommended for women at low or average risk for the disease.
Older women; women with a family history of breast cancer in a mother, sister, or daughter; and women with a history of atypical hyperplasia on a breast biopsy are at increased risk for breast cancer. Younger women, women who have no predisposition to blood clots in the legs or lungs (thromboembolic events), and women who do not have a uterus are at decreased risk for the adverse effects of chemoprevention. A risk assessment instrument developed by the National Cancer Institute (http://www.cancer.gov/bcrisktool) can help estimate cancer risk based on age, family history, and other risk factors.
In general, the balance of benefits and harms of chemoprevention is more favorable for women in their 40s who are at increased risk for breast cancer and have no predisposition to blood clots in the legs or lungs, and for women in their 50s who are at increased risk for breast cancer, have no predisposition to thromboembolic events, and do not have a uterus.
Clinicians should weigh a woman's risk for breast cancer against her risk for adverse effects of chemoprevention.
Potential harms of tamoxifen and raloxifene are increased risk for blood clots in the legs or lungs and hot flashes. Tamoxifen increases the risk for endometrial cancer. The USPSTF found more evidence for the benefits of tamoxifen than for the benefits of raloxifene.
Tamoxifen is the only medication approved by the U.S. Food and Drug Administration (FDA) specifically for the chemoprevention of breast cancer. Raloxifene currently is approved by the FDA only for the prevention and treatment of osteoporosis. A large trial of raloxifene currently is underway in an effort to confirm early results indicating it may also protect against breast cancer. The STAR trial, an ongoing study, is recruiting women to compare tamoxifen to raloxifene for safety and efficacy in preventing breast cancer.
Breast cancer chemoprevention was not considered by the previous USPSTF. Since the previous Task Force completed its work in 1996, several important trials of the efficacy of breast cancer chemoprevention in women who have never had the disease have been published. Researchers have known that tamoxifen medications can prevent a second breast cancer in women who have already had breast cancer—only recently have studies been done to see whether medications can prevent a first breast cancer in women at high risk for the disease.
For more information on breast cancer risk and chemoprevention, contact the following organizations:
healthfinder®
http://www.healthfinder.gov
National Cancer Institute
National Institutes of Health
National Cancer Institute Breast Cancer Risk Tool ("Gail Model")
http://www.cancer.gov/bcrisktool or 1-800-4-CANCER
Members of the USPSTF represent the fields of family medicine, gerontology, obstetrics-gynecology, pediatrics, nursing, prevention research, and psychology. Members of the USPSTF are:
Alfred O. Berg, M.D., M.P.H., Chair
Janet D. Allan, Ph.D., R.N., C.S., Vice-chair
Paul S. Frame, M.D.
Charles J. Homer, M.D., M.P.H.
Mark S. Johnson, M.D., M.P.H.
Jonathan D. Klein, M.D., M.P.H.
Tracy A. Lieu, M.D., M.P.H.
Cynthia D. Mulrow, M.D., M.Sc.
C. Tracy Orleans, Ph.D.
Jeffrey F. Peipert, M.D., M.P.H.
Nola J. Pender, Ph.D., RN
Albert L. Siu, M.D., MSPH
Steven M. Teutsch, M.D., M.P.H.
Carolyn Westhoff, M.D., M.Sc.
Steven H. Woolf, M.D., M.P.H.
AHRQ Publication No. APPIP02-0024
Current as of June 2002
Internet Citation:
Breast Cancer Chemoprevention. What's New from the USPSTF. AHRQ Publication No. APPIP02-0024, June 2002. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/clinic/3rduspstf/breastchemo/brchemowh.htm
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