Letrozole surpasses tamoxifen in head-to-head breast Ca trial.(Gynecology)

The aromatase inhibitor letrozole compares favorably with tamoxifen as an adjuvant treatment for hormone receptor-positive breast cancer in postmenopausal women, reported Dr. Beat Thurlimann and associates in the Breast International Group 1-98 trial.

Interim results of this multinational phase III clinical trial at the 2-year mark "indicate that letrozole is an effective option for standard adjuvant therapy, with a relatively favorable safety profile," compared with tamoxifen. Letrozole was superior to tamoxifen in decreasing the risk of distant metastases, said Dr. Thurlimann of the Swiss Group for Clinical Cancer Research and the Senology Center of Eastern Switzerland, Kantonsspital, St. Gallen, and associates.

Letrozole (Femara) was approved in December for adjuvant treatment of early hormone-sensitive breast cancer in postmenopausal women, based on the results of the BIG 1-98 trial. The trial involved 8,010 postmenopausal women with invasive breast cancer that was positive for estrogen receptors, progesterone receptors, or both. The women were randomly assigned to receive one of three regimens after surgery: monotherapy with either letrozole or tamoxifen for 5 years, letrozole for 2 years followed by tamoxifen for 3 years, or tamoxifen for 2 years followed by letrozole for 3 years.

This planned interim analysis compared outcomes after a median of 26 months for the 4,003 women assigned to letrozole initially with those of the 4,007 assigned to tamoxifen initially (New Engl. J. Med. 2005;353:2747-57).

Disease-free survival was significantly ...