Focus on anastrozole: An aromatase inhibitor for the treatment of hormonally dependent advanced breast cancer

Anastrozole is a potent, selective, nonsteroidal aromatase inhibitor recently approved by the FDA for the treatment of hormonally dependent advanced breast cancer in postmenopausal women. The drug selectively inhibits the cytochrome P450 enzyme aromatase (estrogen synthetase) and has been shown to significantly decrease estradiol levels in postmenopausal women. Unlike aminoglutethimide, anastrozole does not inhibit cortisol concentrations and concomitant administration of corticosteroids is unnecessary. Preliminary data suggest it is as efficacious as megestrol acetate and may be better tolerated. Long-term complications associated with anastrozole's use remain to be determined. Anastrozole's initial place in therapy is for postmenopausal women with advanced breast cancer who have had disease progression despite tamoxifen therapy.