Overview from the International Conference on Long-Term Tamoxifen Therapy for Breast Cancer.

The development of tamoxifen therapy to treat selected patients, with all stages of breast cancer, has provided the clinical community with an efficacious and safe drug for long-term therapy. Issues of safety are under constant review, but justified concerns about high doses of tamoxifen acting as a promoter of liver cancer in rats or as a promoter of endometrial cancer in women have not, as yet, proved to be of clinical relevance. The situation will continue to be reviewed during the development of the prevention studies in Europe and the United States because an improvement in women's health is the ultimate goal of these programs. The hallmark for the successful development of tamoxifen has been the close cooperation between the laboratory and the clinic. The clinical strategy of long-term tamoxifen therapy is a direct application of a laboratory concept. Furthermore, potential problems in the clinic have been identified in the laboratory, and the clinical community has responded quickly to evaluate the real risks to the patient population. This close cooperation will continue. Issues of drug resistance, new antiestrogen development, and the application of the knowledge about steroid receptors to develop targeted gene therapies are being addressed so that additional treatment approaches for breast cancer will be in place by the turn of the century.