The number of uses of tamoxifen in the prevention and treatment of breast cancer may increase in the light of new data, said investigators at the 32nd Annual Meeting of the American Society of Clinical Oncology [Philadelphia, US; May, 1996]. Data compiled from a number of recent clinical trials have demonstrated that tamoxifen may have a role in treating breast cancer in premenopausal, as well as postmenopausal, women. However, in the premenopausal population, its efficacy may be slightly lower than that seen in postmenopausal women. Other study data presented at the conference provided new information on the optimal duration of treatment and the agent's long-term tolerability profile.