Since the 1970s, the drug tamoxifen has been used for treating the recurrence of breast cancer in women. Now, ongoing research is trying to determine whether tamoxifen is effective in preventing breast cancer in women with no personal history of the disease.
For a better understanding of the drug, I consulted Dr. Kathy Helzlsouer, an epidemiologist and medical oncologist at the Johns Hopkins School of Public Health in Baltimore.
Q: Has tamoxifen proved to be an effective treatment?
A: Tamoxifen has been used to treat breast cancer for more than 20 years. Repeated clinical trials of women with breast cancer have shown that tamoxifen reduces the occurrence of a new cancer in the opposite breast.
Ancillary benefits from this drug include a lowered rate of bone loss in postmenopausal women, and lowered cholesterol levels, which could help prevent cardiovascular disease.
Q: What side effects have been reported?
A: Young women may experience some menopausal symptoms, including hot flashes, night sweats and vaginal dryness. Postmenopausal women, who have long since put these symptoms behind them, may experience them again. Another, more serious side effect is the increased risk of endometrial cancer (cancer of the uterine lining). Women on tamoxifen should be monitored closely for any uterine changes.
Q: Has the drug proved useful in prevention?
A: The benefits of tamoxifen in the prevention of breast cancer in women with no personal history of the disease are not established. A large multicenter clinical trial sponsored by the National Cancer Institute started about three years ago, and is scheduled to continue for another five to 10 years. Because of tamoxifen's potentially serious side effects, use of the drug as a preventive measure is not recommended outside of ongoing studies.
Dr. Matanoski is a physician and epidemiologist at the Johns Hopkins School of Hygiene and Public Health. She is founding director of its Institute for Women's Health Research and Policy.