Breast Cancer Prevention

We all dream of a day when breast cancer is a preventable disease.  Despite better understanding of the biology of breast cancer, that hasn't happened, and we don’t know how to prevent the disease.  However, some important advances can reduce the risk of developing it. Some of these, such as lifestyle, diet, and exercise, were discussed in the Common Breast Cancer Risk Factors section.

This section focuses on the medical efforts and interventions that can reduce the risk of developing breast cancer in women who are known to have increased risk.

 
Chemoprevention includes:

Anti-estrogens
In general, the most common non-surgical approach to reducing breast cancer risk is by lowering a woman's level of estrogen and/or the length of time that her breast tissue is exposed to estrogen.  This reduction can happen naturally through pregnancy, late menstruation or early menopause.  Some drugs block the ability of the body to produce or use estrogen.  These drugs are called chemo-preventives.

Several years ago, doctors discovered that the drugs tamoxifen and raloxifene are very effective in preventing a recurrence of breast cancer in women with estrogen receptor positive (ER+) breast cancer.  They used that knowledge to conduct clinical trials to determine that these “anti-estrogen” drugs significantly lower the risk of breast cancer for high risk women.

Side effects and risks are associated with taking both drugs.  Tamoxifen increases the risk of developing uterine cancer, blood clots, strokes and cataracts – and that risk increases with age.  Raloxifene does not appear to increase the risk of uterine cancer, but is associated with a higher incidence of blood clots, especially in the lungs.

 
Aromatase Inhibitors (AIs)
These drugs have been used successfully to lower the risk of a new breast cancer or recurrence in post-menopausal women.  They work by blocking the body's ability to make estrogen.  A recent study demonstrated that when women who are at high risk for developing breast cancer take aromatase inhibitors, their risk of developing invasive breast cancer is reduced by 64% – better than the result achieved with anti-estrogens.  AIs do not increase the risk for other cancers or blood clots, but can cause menopausal symptoms such as hot flashes and vaginal dryness and can contribute to osteoporosis.

Doctors and researchers are encouraged by the very positive results of the clinical trials using aromatase inhibitors.  They acknowledge, though, that for any woman, and especially one who is healthy, taking a drug that may cause unpleasant symptoms is not an easy decision.  Every woman should be aware of her own risks and weigh the benefits and potential side effects of taking these drugs after discussing her situation with her physician.

 
Prophylactic Surgery
For women at very high risk of developing breast cancer, including those who are positive for BRCA1 or BRCA2 or have a very strong family history of the disease, surgery to remove both breasts (prophylactic mastectomy) or the ovaries (prophylactic oophorectomy) is an option.  Removing the breast tissue greatly reduces (but does not totally eliminate) the possibility of developing breast cancer.  Removing the ovaries significantly lowers the body's level of estrogen and reduces the risk of developing breast cancer.

Making the decision to have this kind of radical surgery, which often occurs in relatively young women, is very difficult.  It should be made only after a full assessment of the risks, adequate counseling by professionals trained in cancer genetics and a thorough discussion of all the options available for risk reduction and follow up.