Anastrozole in the management of breast cancer

Anastrozole (Arimidex™, AstraZeneca) is a third-generation aromatase inhibitor which rapidly reduces oestradiol concentrations to below detectable levels. It is both potent and selective for the aromatase enzyme, with near-maximal suppression of serum oestrogens occurring at the clinical dose of 1 mg/day in postmenopausal women with advanced breast cancer. Anastrozole has also been shown to be a potent suppressor of intratumoural oestrogens, with responses comparable to those in serum. The results of two large, identically designed, randomised trials in postmenopausal women with advanced breast cancer who had progressed on tamoxifen showed that oral anastrozole 1 mg/day produced a statistically significant survival advantage over megestrol acetate 40 mg q.i.d. The median duration of survival was 26.7 months for anastrozole versus 22.5 months for megestrol acetate. Anastrozole was as well-tolerated as megestrol acetate, while weight gain was significantly increased in the megestrol acetate group compared w...