Experience with aromatase inhibitors in the treatment of advanced breast cancer.

Inhibition of the aromatase enzyme system has become an established means of hormonal treatment for hormone-responsive advanced breast cancer. The widest clinical experience is with aminoglutethimide, which achieves around 30% objective remissions of metastatic disease for up to 1 year. Due to the sometimes serious side-effects of this drug, preclinical and clinical investigations have been undertaken and have yielded a number of steroidal and non-steroidal aromatase inhibitors that have been shown in early or mature clinical trials to give objective disease remissions similar to those with aminoglutethimide but with less toxicity. There is thus good reason to believe that newer aromatase inhibiting drugs will soon be available for routine use in patients with breast cancer. This paper summarizes our experience and reviews data from other groups.