ASCO 2011 Report: Breast Cancer

Exemestane Reduced Risk for Breast Cancer in Postmenopausal Women

The double-blind, placebo-controlled, phase III NCIC CTG MAP.3 trial compared the use of the steroidal aromatase inhibitor exemestane with placebo in 4560 postmenopausal women who had elevated risk for developing breast cancer. Prespecified risk factors included age ≥60, Gail risk score >1.66%, or prior intraepithelial neoplasia (lobular or ductal carcinoma in situ or atypical lobular or ductal hyperplasia).

After a median follow-up of 35 months, exemestane recipients achieved a 65% reduction in breast cancer risk, compared with placebo recipients (annual incidence, 0.19% vs. 0.55%; hazard ratio, 0.35; P=0.002). Exemestane recipients experienced no excess incidence of estrogen …