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Overview of Preventive Options for Breast Cancer

Scientists do not yet know what causes breast cancer, and consequently, there are no general guidelines that women can follow to prevent the disease. However, researchers have identified several factors, some controllable and others uncontrollable, that can increase the risk of developing breast cancer. Therefore, the most practical strategy for most women is to reduce the controllable risk factors for breast cancer and follow the screening guidelines set forth by the American Cancer Society and other organizations to help detect breast cancer in its earliest stages when the chances for successful treatment and survival are the greatest. For eligible women at especially high risk of breast cancer, there a number of options that may help prevent breast cancer. These options include:

Because each of these options may cause side effects and/or permanent, unalterable consequences, they should be carefully discussed with physicians and other healthcare providers. No option can provide 100% protection against breast cancer.

Risk Factors and Early Breast Cancer Detection Guidelines

Many factors can influence a woman's risk of getting breast cancer, but having one or more risk factors  does not necessarily mean that a woman will get breast cancer. Some women with one or more breast cancer risk factors never develop the disease, while the majority of women with breast cancer (approximately 80%) have no apparent risk factors.

Uncontrollable risk factors:

Controllable risk factors:

  • Having a first child after 30 or never having children
  • Alcohol consumption
  • High fat diet/obesity
  • Long term use of hormone replacement therapy (more than five years)

Following the American Cancer Society screening guidelines can help detect breast cancer early, when the chances for successful treatment and survival are the greatest. Mammography helps detect approximately 85% of all breast cancers and should be supplemented with regular clinical breast exams and breast self-exams.

Guidelines for early breast cancer detection:

  • All women between 20 and 39 years of age should practice monthly breast self-exams and have physician performed clinical breast exams at least every three years.
  • All women 40 years of age and older should have screening mammograms every one to two years, practice monthly breast self-exams, and have yearly clinical breast exams. The clinical breast exam should be conducted close to and preferably before the scheduled mammogram
  • All women 50 years of age and older should have annual screening mammograms, practice monthly breast self-exams, and have yearly clinical breast exams. The clinical breast exam should be conducted close to and preferably before the scheduled mammogram

Younger women with a family or personal history of breast cancer should talk to their physicians about beginning annual mammograms before age 40.


The drug tamoxifen is approved by U.S. Food and Drug Administration (FDA) to help prevent breast cancer in women 35 years of age or older who are at high risk of the disease as determined by a physician. By blocking estrogen in the breast, tamoxifen helps prevent the growth and reproduction of breast cancer cells. In a study of 13,388 women at high risk of breast cancer, tamoxifen was able to reduce the incidence of breast cancer by 49%.

Tamoxifen is available in pill form. The typical daily dose of tamoxifen for women at high risk for breast cancer is 20 milligrams daily for up to 5 years. The most common side effect of tamoxifen is a higher occurrence of hot flashes. Other side effects include vaginal irritation or dryness and irregular menstrual cycles. In addition to these side effects, tamoxifen is associated with a slight increased risk of endometrial cancer (cancer of the uterine lining) and other serious complications. Women who are considering tamoxifen to help prevent breast cancer should discuss the benefits and risks of the drug with their physicians.

  Click here for general information on tamoxifen.

  Click here to learn more about the side effects of tamoxifen.

STAR Trial

STAR (Study of Tamoxifen and Raloxifene) is a randomized, double-blind study that will include 22,000 post-menopausal women (age 35 or older) who are at high risk for developing breast cancer, as determined by a physician. The study will compare the safety and effectiveness of tamoxifen and a similar drug, raloxifene (brand name, Evista). Raloxifene is already FDA approved to help treat osteoporosis, a degenerative bone disease. Research suggests that raloxifene may also help prevent breast cancer.

Currently, over 6,000 women have already enrolled in STAR and researchers are hoping another 16,000 women will join within the next few years. The STAR trial is being conducted by the National Adjuvant Breast and Bowel Project (NSABP). Eligible women may enroll at one of more than 500 centers in the United States, Canada, and Puerto Rico.

  Click here for more information on STAR, including eligibility requirements and how to enroll.

Prophylactic Mastectomy

Prophylactic mastectomy (also called preventive mastectomy) is the surgical removal of both breasts to help prevent breast cancer. This procedure is controversial among some members of the medical community, but it is generally accepted that those women who are at very high risk of breast cancer and very worried about developing the disease may benefit from prophylactic mastectomy.

Recent research from the Mayo Clinic in Rochester, Minnesota shows that surgically removing both breasts can reduce the risk of breast cancer by up to 90%. However, having a prophylactic mastectomy does not guarantee that a woman will never develop breast cancer. It is impossible for surgeons to remove every breast cell during mastectomy. Although most of the breast cells are removed, it is possible for breast cancer to develop from those few remaining cells.

  Click here to learn more about prophylactic mastectomy.


Oophorectomy is the removal (ablation) of the ovaries. The procedure has been practiced in Europe for years to help prevent breast cancer and may become more common in the U.S. as researchers continue to study the effects of the oophorectomy. The theory is that removing the body’s main source of estrogen (ovaries) will help reduce the chances of developing breast cancer since many breast cancers depend on estrogen for growth and survival.

Current research suggests that oophorectomy may reduce the risk of breast and ovarian cancer in women who test positive for BRCA1 (breast cancer gene 1) or BRCA2 (breast cancer gene 2) gene mutations. However, oophorectomy is not standard procedure in the U.S. and tamoxifen is a more accepted option for helping to prevent breast cancer. Researchers are also investigating whether oophorectomy may help prevent a recurrence of breast cancer in pre-menopausal women who have a personal history of the disease.

 Click here to learn how to perform a search of the most recent medical journal articles on oophorectomy.

Updated: September 12, 2007