Anastrozole is used in the treatment and prevention of breast cancer in women. The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial was of localized breast cancer and women received either anastrozole, the selective estrogen receptor modulator tamoxifen, or both for five years, followed by five years of follow-up. After more than 5 years the group that received anastrozole had better results than the tamoxifen group. The trial suggested that anastrozole is the preferred medical therapy for postmenopausal women with localized estrogen receptor-positive breast cancer.
Anastrozole is used at a dosage of 0.5 to 1 mg/day in combination with the antiandrogenbicalutamide in the treatment of peripheral precocious puberty, for instance due to familial male-limited precocious puberty (testotoxicosis) and McCune–Albright syndrome, in boys.