Breast cancer prevention by antihormones and other drugs: where do we stand?

Breast cancer is the most common cancer in women worldwide. The selective estrogen-receptor (ER) modulators tamoxifen and raloxifene are approved by the Food and Drug Administration for the preventive therapy of breast cancer. Other drugs have shown promise but need further assessment. In the present review, we present an update of the chemoprevention of ER-positive breast cancer and discuss the potential role of metformin and aspirin, 2 drugs other than the specific "antihormones."