Aromatase inhibitors for hormonal therapy of early-stage breast cancer.

Aromatase inhibitors block estrogen synthesis by inhibiting aromatase, the enzyme responsible for the conversion of adrenal steroids to estrogen. They are approved for the first-line treatment of metastatic breast cancer in hormone receptor-positive women. Three large, well-designed randomized trials have been reported which support the use of aromatase inhibitors in the treatment of early stage breast cancer. This review focuses on data on aromatase inhibitors in the adjuvant setting and looks to the future potential of these drugs in both ductal carcinoma in situ and chemoprevention.