BMAs should be considered for the following patients with primary breast cancer: Premenopausal OR postmenopausal at high risk (i.e., 10-year fracture risk >20% OR prior fragility fracture of hip or spine OR more than one fragility fracture) and postmenopausal at moderate risk (i.e., 10-year fracture risk 10%–20%) OR a T-score lower than −2.0, AND undergoing aromatase inhibitor therapy for breast cancer. This evidence concerns the gene CYP19A1 and breast cancer.