Adjuvant Therapy for Breast Cancer: Will Anastrozole Replace Tamoxifen?

Aromatase inhibitors block the synthesis of estrogen from androgens in postmenopausal women. One such drug, anastrozole, has been shown to be effective in treating metastatic breast cancer and is associated with a lower risk for thrombotic and uterine morbidity than tamoxifen, the current standard adjuvant therapy for women with hormone-sensitive breast cancer. This international trial, sponsored by the manufacturer of anastrozole and tamoxifen, was designed to compare the safety and efficacy of the 2 drugs in the adjuvant setting. A total of 9366 postmenopausal women who had completed primary therapy for invasive operable breast cancer were randomized to receive anastrozole alone, tamoxifen alone, or anastrozole plus tamoxifen. Baseline de…