By Elizabeth Smoots, M.D.
What's New in Breast Cancer Prevention?
Breast cancer is scary business. Most of my female patients fear it even more than heart disease, which kills up to five times more women. The facts are unsettling: Every year, about 180,000 women develop breast cancer and about 43,000 die from the disease. In the United States, breast cancer is the most common type of cancer in women and the second-leading cause of cancer deaths. Currently, one in nine women will develop breast cancer during their lifetime.
Scientists still don't know what causes a breast cell to start growing and turn into a malignant tumor. Studies suggest that in certain situations the female hormone estrogen can stimulate breast cancer cells to grow and spread. The good news is that advances in the field of prevention offer hope for women who are at increased risk for breast cancer.
A new development for prevention is an anti-estrogen drug called tamoxifen. The medication blocks the effect of estrogen on breast tissue. Tamoxifen has been used for more than 20 years to both treat breast cancer and to prevent its recurrence.
New data from a large, government-sponsored study show that tamoxifen can also help prevent breast cancer in healthy women who are at high risk for developing the disease. In a five-year study involving 13,338 high-risk women, those who took tamoxifen had a 49 percent reduced incidence of breast cancer. The Food and Drug Administration recently approved tamoxifen for use in healthy, high-risk women (see risk factors below). Until more-definitive research is completed, experts recommend limiting the use of tamoxifen to five years.
Unfortunately, tamoxifen can have adverse effects. Women in the study who were given tamoxifen had more than twice the rate of uterine cancer as those who were given a placebo. There was also a higher risk of strokes, blood clots, and cataract surgery -- mostly in women over age 50. Other possible effects include hot flashes and vaginal discharge or dryness. These side effects may be viewed as risks in and of themselves, but for high-risk women who would consider having a double mastectomy as preventive therapy, tamoxifen might be a more palatable option. Also, tamoxifen can't currently be taken with estrogen replacements or birth control pills, which could interact with the drug.
Other drugs are being tested that may prove as effective as tamoxifen but have fewer side effects. A five-year study is currently underway to compare the new drug raloxifene with tamoxifen in breast cancer prevention. Early data suggest that raloxifene may protect the breast without causing any associated increased incidence of uterine cancer. Raloxifene is currently approved only for use in the prevention of osteoporosis.
Risk factors for breast cancer
If you think you may be at increased risk for breast cancer, contact your health care provider for an evaluation. The pros and cons of tamoxifen therapy depend on your individual risk and health status. Factors used in the prevention trials to calculate a woman's risk of breast cancer include the following:
Age 60 years or older
Early onset of periods (before age 12)
Having no children or first childbirth after age 29
Family history of breast cancer (in a mother, sister, or daughter)
Previous breast biopsy for any reason
Several other factors can place a woman at increased risk for breast cancer. These include a history of previous breast cancer, obesity, radiation exposure, or excessive alcohol intake. In addition, women who go through menopause after age 54 or who use estrogens for a long time after menopause may have an increased chance of developing the disease.
All women can reduce their chances of developing breast cancer through simple lifestyle choices. Behaviors that may help reduce your risk include eating a diet rich in fruits and vegetables, maintaining a healthy weight, exercising regularly, reducing your consumption of fat and animal protein, and limiting your alcohol intake to one glass or less a day.
In the event that cancer is ever present, getting regular medical care can improve your chances of recovery. This includes mammography (often recommended annually after age 39), regular breast exams by your care provider, and monthly breast self-exams .
Know the signs of breast cancer
Call your health care provider right away if you notice any symptoms of breast cancer:
A lump or thickening in the breast
Dimpling or puckering of the skin
Change in skin color or texture
Change in breast shape
Swelling, redness, or a sensation of heat in the breast
Scaly skin or a rash on or around the nipple*
Localized breast pain, not related to your hormone cycle
* Signs of Paget's disease of the nipple, a rare form of breast cancer in women
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