Abstract
Although tamoxifen was the standard endocrine treatment for breast cancer for more than 30 years, aromatase inhibitors such as anastrozole now have an important therapeutic role in postmenopausal women. Anastrozole gained initial acceptance for use in advanced breast cancer, but subsequent studies have shown that, in early breast cancer, anastrozole is superior to tamoxifen as initial adjuvant therapy for newly diagnosed patients, while patients already receiving treatment benefit from switching to anastrozole rather than continuing with tamoxifen or from extending therapy with anastrozole after 5 years of tamoxifen. Additionally, in the neoadjuvant setting, anastrozole may reduce tumor size in patients with locally advanced disease. Current studies are focusing on possible uses of anastrozole in breast cancer prevention and combination treatments.