Long-Term BIG I-98 Results Show Letrozole Benefit

BERN, Switzerland—Long-term (median, 51 months) follow-up data from the Breast International Group (BIG) I-98 trial support earlier findings that the aromatase inhibitor letrozole (Femara) is more effective than 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).