Tamoxifen therapy in breast cancer control worldwide.

In most developed and many developing countries, breast cancer is the most frequent cancer and the leading cause of cancer death among women. At least 50% of all breast cancer patients worldwide would survive longer, however, if public awareness about and early detection of the condition were increased and greater use were made of efficient treatment of proven value. With early-stage, localized breast cancer, local treatment combined with adjuvant hormonal therapy with tamoxifen, a synthetic estrogen, could save the lives of 6 women out of 100 compared with local treatment alone. Tamoxifen has anti-estrogenic effects not only on breast cancer cells but also on liver metabolism and bone, with concomitant decreases in risk factors for chronic skeletal and vascular system diseases. Long-term tamoxifen treatment causes major adverse clinical effects in < 5% of women; menopausal and vasomotor symptoms occur in the majority of treated women, but their severity lessens over time. Tamoxifen is being considered as a standard therapy and is included in the WHO list of essential drugs for the treatment of breast cancer patients in both developing and developed countries. For the control of breast cancer more successfully worldwide, one challenge is to make tamoxifen therapy available to greater numbers of women.