Breast cancer remains a major cause of mortality and morbidity, and may be amenable to chemoprevention as estrogen stimulation is believed to be responsible for the promotion of this disease. Tamoxifen is the most widely studied compound for chemoprevention and clinical trials involving over 20,000 women world-wide are currently underway. This drug is well-tolerated with low acute toxicity and high compliance, and has a favorable profile in both decreasing serum cholesterol and increasing bone mineral density in postmenopausal women. However, there are fears of its potential carcinogenicity, especially an increased risk of endometrial cancers, which may jeopardize further recruitment and compliance of women in these chemoprevention studies. Meta-analyses of these studies are expected to be conducted in the year 2000 to address the efficacy of tamoxifen in women with an increased familial predisposition and in those with known germline BRCA mutations.
