Prevention research

Many of the factors that influence your chances of developing breast cancer-your age, a family history of breast cancer, the age at which you began to menstruate-are beyond your control. Others, however, present opportunities for change, and several large research trials are looking at possibilities for "intervention."

The Breast Cancer Prevention Trial is a randomized study of tamoxifen, a drug that has been widely used in the treatment of women with breast cancer. Because tamoxifen has been found to markedly reduce the occurrence of new cancers in the opposite breast of women who have already had breast cancer, it is now being tried as a preventive in healthy women at increased risk for breast cancer because they are 60 or older or are younger but have combinations of other risk factors. (Tamoxifen also appears to offer protection against heart attacks and osteoporosis.)

Dietary "chemoprevention" is being tested in Italy, where women who have already been treated for breast cancer are taking 4-HPR, a synthetic form of vitamin A, in hopes of preventing cancer from developing in the opposite breast. Other researchers are investigating the protective potential of several other vitamins, including C and E as well as beta-carotene, the form of vitamin A found in fruits and vegetables. Yet other scientists are checking out naturally occurring chemicals, called phytochemicals, found in common fruits, vegetables, and other edible plants, in hopes of finding cancer-fighting substances that can be extracted, purified, and added to our diets.

Diet itself is another target of prevention research. In the Women's Health Initiative, a project of the National Institutes of Health, 70,000 women over 50 are being enrolled in a series of clinical trials to measure the effectiveness of a low-fat diet (less than 20 percent of calories from fat) and calcium plus vitamin D supplements, along with hormone replacement therapy, in combatting heart disease and osteoporosis as well as cancer. Another large trial evaluating a low-fat diet in high-risk women is under way in Canada.

A much more drastic approach to breast cancer prevention is surgery to remove both breasts. Such a procedure, known as prophylactic mastectomy, is sometimes chosen by women with a very high risk for breast cancer-for instance, having a mother and one or more sisters with bilateral premenopausal breast cancer, plus a diagnosis of atypical hyperplasia and a history of several breast biopsies.

Unless a woman finds that anxiety is undermining the quality of her life, she is usually counseled not to choose this physically and psychologically draining surgery. The vast majority of breasts removed prophylactically show no signs of cancer. Moreover, since even an ordinary ("total") mastectomy can leave a small amount of breast tissue behind, it cannot guarantee the woman will remain cancer-free. The preferred approach for most high-risk women is careful surveillance with clinical breast exams and mammography once or twice a year. Also, monthly breast self-examinations are performed.

If you are considering a prophylactic mastectomy, with or without subsequent breast reconstruction, you will want to get a second opinion, preferably from a breast specialist. There is seldom reason to rush your decision. Many doctors advise a woman to give herself several months to weigh the options.

Preventive steps

Whether your risk of breast cancer is low or high, there are some preventive steps you can take:

You can follow early detection practices. Request mammograms-every 1-2 years if you are age 40 or older, and every year if age 50 or older; get yearly breast exams by a doctor or nurse; and perform monthly breast self-exams.

If your risk is elevated, you can enroll in one of the prevention trials; for information, call the Cancer Information Service at 1-800-4-CANCER.

In making decisions about hormone-containing drugs, you can consult your doctor about your personal situation and carefully weigh any potential risks against the benefits. You can stay informed as new research findings become available.

You can lose excess weight, eat a balanced diet that provides a good variety of nutrients and plenty of fiber, limit dietary fat, and drink alcohol only in moderation. These are "good health" measures that make sense for everyone.