Abstract
Selective estrogen receptor modulators (SERMs) are compounds that display mixed estrogen agonist/antagonist activity. Currently, four SERMs are licensed for clinical use: tamoxifen, toremifene, clomifene and raloxifene. The STAR and RUTH trials have provided useful data about the potential role of SERMs in the primary prevention of breast cancer and cardiovascular disease in postmenopausal women. New-generation SERMs, such as bazedoxifene, arzoxifene, lasofoxifene and ospemifene, are currently being evaluated. The aim is to find a SERM that conserves the skeleton and prevents breast cancer without increasing the risk of endometrial cancer and venous thromboembolism, and without inducing hot flushes. Technological advances in the study of estrogen receptor activation will provide key information for drug development.