Update on Estrogen Receptor–Positive Breast Cancer Risk Reduction

Women who are at increased risk of breast cancer can be identified using individual risk factors or by using validated quantitative risk assessment models. There are millions of such women in the US population alone, and many additional millions of women at increased risk worldwide. Decades of randomized, prospective studies of these women using selective estrogen receptor modulators (SERMs) have shown that risk can be reduced safely and effectively by 50% for all invasive breast cancer and by nearly 70% or more for estrogen receptor–positive breast cancer. Safety and tolerability of the SERMs are acceptable in the published studies, and two SERMs, tamoxifen and raloxifene, are approved by the US Food and Drug Administration for breast cancer risk reduction. Nevertheless, the drugs are not widely used despite reasonable cost per year of life saved (or morbidity avoided). Clinicians must endeavor to identify women who are suitable candidates for these drugs and educate them about their safety and utility.