The Estrogen Receptor: A Logical Target for the Prevention of Breast Cancer with Antiestrogens

A strategy for the prevention of breast cancerhas been refined over the last century beginning withthe first observation that oophorectomy caused diseaseregression in some patients, to the identification of the estrogen receptor some 60 years later,and finally to the synthesis of the first nonsteroidalantiestrogen. Tamoxifen was the first clinically usefulantiestrogen and has been used for the treatment of breast cancer for the last twenty-one yearsin the United States. It is therefore a logicalprogression that antiestrogens are now recognized asuseful agents for the prevention of breast cancer. We will discuss the estrogen receptor as a targetfor the treatment and now the prevention of breastcancer. Data from the National Surgical and BowelProject (NSABP)⁴ tamoxifen prevention trial will be discussed with the preliminary resultsof two other European studies. The status of breastcancer prevention to date involves the comparison of thecurrent standard of prevention, tamoxifen, with the osteoporosis prevention drug, raloxifene inan ongoing trial called Study of Tamoxifen andRaloxifene (STAR).