Update on the current use of hormonals as therapy in advanced breast cancer.

Hormonal agents have a confirmed role in the management of postmenopausal women with receptor-positive advanced breast cancer. Until recently, tamoxifen has been the accepted agent for treating these patients. However, accumulating evidence suggests that the new antiaromatase agents will replace the antiestrogens as the preferable option in hormone-naive patients. Comparative trials indicate that the aromatase inhibitors, anastrozole and letrozole, and the aromatase inactivator, exemestane, have at least equivalent efficacy to tamoxifen with similar or superior tolerability. These agents are also more effective than the progestin, megestrol acetate, when studied in patients progressing on tamoxifen. The improved aromatase selectivity and high potency of these antiaromatase agents when compared with earlier agents have resulted in improved efficacy and tolerability. Additionally, no cross-resistance has been reported between the antiaromatase agents and tamoxifen or, in some instances, among the antiaromatase agents themselves. The role of antiaromatase agents will certainly expand in the near future to include not only treatment of metastatic breast cancer, but use in the adjuvant and neoadjuvant settings as well, and, ultimately, breast cancer prevention. The results of ongoing investigations are awaited with interest.