Defining the role of raloxifene for the prevention of breast cancer

In summary, the CORE trial provides additional results that indicate that raloxifene reduces breast cancer incidence in postmenopausal women with osteoporosis. The data suggest that this benefit continues with additional treatment (up to 8 years) with raloxifene and that the safety profile of long-term raloxifene use is similar to that seen in the MORE trial. Thus, for postmenopausal women with osteoporosis, raloxifene is a reasonable choice to treat osteoporosis and also to reduce the risk of breast cancer. Should postmenopausal women who do not have osteoporosis but are at increased risk of breast cancer receive raloxifene to prevent breast cancer? At this time, the results of the CORE trial do not help to answer this question because all of the women enrolled in the CORE trial had osteoporosis. For women without osteoporosis who are at high risk of breast cancer, tamoxifen, in our opinion, remains the "gold standard" chemoprevention agent to reduce the risk of breast cancer in high-risk pre- and postmenopausal women. We anticipate that the results of several large-scale chemoprevention trials will help clarify the role of raloxifene, as well as other hormonal agents, for breast cancer prevention.