Prevention of breast cancer with tamoxifen: the Italian study in hysterectomized women

Tamoxifen is one of the most successful and studied anticancer drugs. In patients with breast cancer it helps prolong survival, and there is persuasive evidence that it can reduce the incidence of contralat- eral new primaries. Inhibition or reversal of breast carcinogenesis with tamoxifen appears currently to be the most potentially successful chemopreventive strategy for this important disease. To assess the efficacy of the drug in this respect and to evaluate the risk/benefit ratio of its use in healthy women, three major studies have been designed, in the UK, in the USA and in Italy. In all of them the participants receive either 20 mg/day tamoxifen or placebo, in a double blind study, for 5 years. While the US and the UK trials are enrolling high-risk women only, the Italian study will accept any woman between 35 and 70 years of age, provided she has had a hysterectomy for benign conditions. This is to avoid the risk of endometrial cancer caused by tamoxifen, which appears to be the most dangerous side effect of this agent. The aim of the Italian study is to evaluate first the preventive efficacy of tamoxifen and to address the costs and benefits of this approach. The Italian trial is coordinated by the European Institute of Oncology in Milan and by 30 June 1995 more than 4000 subjects had been randomized.