CHICAGOOf the three primary methods of preventing breast cancer that are being debated today, only onelifestyle educationis suitable at present for the general population of women.
Active chemoprevention with tam-oxifen (Nolvadex) or retinoids should be attempted only in clinical trials because of the potential for side effects, said Grant W. Carlson, MD, professor of surgery, surgical oncology, and plastic surgery, Emory University. Prophylactic mas-tectomy not only is unproved as a preventive measure, it can produce devastating psychological consequences, he noted in his presentation at the annual scientific meeting of the American College of Surgeons.
Breast cancer prevention should begin with public health education on the potentially avoidable causative factors of breast cancer, such as smoking, alcohol consumption, high-fat diet, and sedentary lifestyle, Dr. Carlson said.
Although it is difficult to establish a direct causal relationship between smoking and breast cancer, multiple cohort studies have suggested that cigarette smoking increases the risk for breast cancer, Dr. Carlson said. A large Danish study found that smoking for 30 or more years raised the relative risk of breast cancer by 60%. The Nurses Health Study at Harvard University computed an 80% increase in risk for breast cancer among nurses who smoked at least 25 cigarettes per day.
Consumption of alcohol has also been implicated in the development of breast cancer. According to the Nurses Health Study, women who drank more than one alcoholic beverage per day had a 2.5 times greater risk for breast cancer than did nondrinkers, Dr. Carlson said. A diet high in fat may explain the difference in breast cancer rates among women in western and Asian countries, he added.
Finally, exercise has been thought to reduce the risk of breast cancer by modulating the cycle of ovulation, decreasing the amount of body fat, and possibly inducing a change in immunity. [See box on the role of weight gain in the development of breast cancer.]
Adult Weight Gain Raises Breast Cancer Risk
A new report from the Nurses Health Study shows that women who gain excess weight during adulthood have an increased risk of breast cancer (JAMA, November 5, 1997).
The study followed more than 95,000 nurses, aged 30 to 55 years, for 16 years, during which time 2,517 cases of invasive breast cancer were identified.
Women who gained at least 45 pounds and were not taking estrogen supplements were twice as likely to develop invasive breast cancer as those women who gained 5 pounds or less.