Data for anastrozole come from a preliminary analysis of the Arimidex, tamoxifen alone or in combination (ATAC) trial and show that anastrozole monotherapy is more effective in prolonging disease-free survival than tamoxifen. Of 3,125 women in the anastrozole group, 317 had a relapse of their breast cancer or died compared with 379 of 3,116 women in the tamoxifen group (P=0.0129). Using anastrozole and tamoxifen in combination was not found to be more efficacious than using tamoxifen alone.

New data for letrozole show that the drug may be effective in treating postmenopausal women with HER-2 positive breast cancer. Previous research has shown the benefit of letrozole over tamoxifen (see PJ, 7 October, 2000, p508).