BERN, SwitzerlandLong-term (median, 51 months) follow-up data from the Breast International Group (BIG) I-98 trial support earlier findings that the aromatase inhibitor letrozole(Drug information on letrozole) (Femara) is more effective than tamoxifen(Drug information on tamoxifen) as initial postsurgery therapy for early breast cancer (J Clin Oncol 25:486-492, 2007).
Letrozole reduced recurrence risk by an additional 18% over tamoxifen and risk of distant metastases by an additional 19% in 4,922 postmenopausal women with hormone-sensitive early breast cancer randomized to 5 years of tamoxifen or letrozole (the current analysis did not include sequential treatment patients). Letrozole also significantly improved disease-free survival (DFS) (HR 0.82). In node-positive disease, letrozole reduced recurrence risk by a further 23% vs tamoxifen; in women who received chemotherapy, the reduction was a further 26%. A nonsignificant improvement in DFS also emerged in node-negative patients (12% vs 4% at the initial analysis).