[Raloxifene and breast: from the SERMs concept to its place in clinical practice]

Raloxifene is a second generation Selective Estrogen Receptor Modulator. It is indicated in prevention and treatment of post-menopausal osteoporosis. This drug has an estrogen agonistic effect on bone tissue, an estrogen-antagonistic effect in breast and endometrial tissue. It inhibits estrogen induced breast cells proliferation and, in animal studies, it prevents the growth of chemically induced mammary tumors. Raloxifene has a limited effectiveness in women with advanced breast cancers. The effects of raloxifene after treated breast cancer and sequential use of tamoxifene after raloxifene (or the contrary) are not known and should be tested in specific pre-clinical and clinical studies. In osteoporotic women included in the MORE trial, the risk reduction of hormone-dependent breast cancer due to raloxifene raises the issue of some effectiveness of raloxifene in breast cancer prevention. The STAR trial is currently comparing tamoxifene vs raloxifene in breast cancer prevention in women at increased risk of breast cancer. Like tamoxifene, raloxifene increases the risk of venous thrombo-embolic events. On the other hand, in a subgroup of women at increased vascular risk in the MORE trial, the reduction of cardiovascular events raises the issue of an effect of raloxifene in the prevention of coronary events. The ongoing RUTH trial is testing this assumption and it is comparing raloxifene to a placebo in women at increased vascular risk. Today, in clinical practice, before the results of ongoing trail, raloxifene should be used in the setting of osteoporosis prevention and treatment.