Just the thought of breast cancer strikes fear into the hearts of thousands. Yet knowledge is power, and experts agree that understanding your breast cancer risk is the first step toward protecting yourself.
Suzanne Mahon, R.N., DNSc, a professor of nursing and internal medicine who specializes in oncology, is responsible for cancer prevention activities at Saint Louis University Cancer Center. She notes that a “complete and comprehensive risk assessment” is the foundation for decisions about breast cancer screening programs and preventive options. “Patients have to have an accurate risk assessment and then understand the risks, strengths and limitations of whatever testing protocol they choose,” she says. The most important aspect of creating that risk assessment is family health history, a topic about which many are surprisingly unknowledgeable.
Mahon suggests that every woman put together a complete history by talking with relatives and recording as much information as possible. The Surgeon General’s Family History Initiative, available through the U.S. Department of Health and Human Services Web site (hhs.gov/familyhistory), is a free tool for creating and maintaining a complete health record.
Women who have a significant family history of breast or ovarian cancer, those with several relatives who had the disease or a first-degree relative who was diagnosed prior to menopause, should talk with a risk-assessment counselor. Mahon is one of a handful of trained health professionals in the St. Louis area who specialize in this type of counseling.
While individualized risk assessment is important, there are things we all can do to help mitigate our breast cancer risk. “This is a disease of Westernization,” says Matthew Ellis, Ph.D., of Washington University Physicians. “American women tend to have fewer children and have them later in life; they tend to be relatively sedentary and, as a result, overweight; and they may choose to take hormone therapy during menopause. Those are key modifiable risk factors.”
These risk factors are related to the amount of circulating estrogens in the body, Ellis says. Having fewer children and having them later increases the number of menstrual cycles a woman has prior to lactation, both increasing the amount of estrogen exposure prior to pregnancy and postponing the protective effect of lactation. After menopause, most estrogen comes from fat tissue. Therefore, more fat tissue after menopause can increase estrogen levels, subsequently increasing breast cancer risk. Hormone therapy that contains a combination of estrogen and progestin has been found to increase risk, although scientists continue to examine the effects of specific formulas and duration of treatment.
“There’s an emerging story here that’s quite interesting,” Ellis muses. “Low-dose estrogen alone, without progestin, may not carry as much risk. The issue of hormone therapy is complicated, though. The research findings don’t mean that women can’t use hormone therapy, but the decision is an individual one and must be made in light of a complete discussion of risks and benefits.”
Meanwhile, researchers continue to study potential preventive therapies. “The NSABP (National Surgical Adjuvant Breast and Bowel Project) has conducted two large breast cancer prevention studies,” says Dr. Bethany Sleckman, director of oncology research at St. John’s Mercy Medical Center.
The first study showed that tamoxifen (a drug that interferes with estrogen activity) decreases the risk of invasive breast cancer by about 50 percent in women at high risk. The second study compared tamoxifen to raloxifene (a drug that mimics estrogen in the body and was originally used to treat osteoporosis) and found that the drugs had equal efficacy, but raloxifene had fewer side effects. “Raloxifene is now approved for this indication, as well as for osteoporosis. Here at St. John’s, we enrolled more than 200 women in these two studies,” she says.
New studies are exploring the potential preventive qualities of aromatase inhibitors (AIs), a class of drugs that already have been approved by the Food and Drug Administration for the treatment of hormone-sensitive breast cancer in postmenopausal women. “The hope is that AIs would be more effective than tamoxifen or raloxifene, while eliminating some of the risks of tamoxifen, such as blood clots and uterine cancer,” Sleckman says.
As scientists continue to work on the puzzle of breast cancer prevention, the experts interviewed for this article all stress the importance of annual clinical breast exams and mammograms for women 40 and older. “Take charge of your health,” Sleckman urges. “Ask your doctor to assess your risk of breast cancer and follow the appropriate screening recommendations.”