PROSPECTS FOR THE PRIMARY PREVENTION OF BREAST-CANCER

In this paper, the rationale, stage of development, and known or potential adverse effects of three potential strategies for the prevention of breast cancer are reviewed. Two methods-the use of tamoxifen in postmenopausal women and the use of luteinizing hormone (LH)-releasing hormone agonists in premenopausal women-involve hormonal manipulation. In the premenopausal period, the goal is to reduce the number of ovulatory menstrual cycles a woman experiences in order to reduce her exposure to estrogen and progesterone. Physical activity during adolescence is proposed as a nonhormonal method of accomplishing this. The use of LH-releasing hormone agonists to produce a reversible menopause can also reduce a woman's cumulative exposure to ovarian steroid hormones. Tamoxifen, which is effective in breast cancer therapy, provides endocrine control of estrogen-regulated breast tumor growth. Breast cancer chemoprevention trials using tamoxifen among postmenopausal women have been proposed, and pilot studies are under way.