Letrozole linked to fewer cancers post tamoxifen: more than 5,000 women studied.(Gynecology)

Postmenopausal breast cancer survivors who took the aromatase inhibitor letrozole following a 5-year course of tamoxifen therapy had significantly fewer new and recurrent cancers, as well as a trend toward lower overall mortality, compared with women taking a placebo, Dr. Paul E. Goss and associates reported.

The trial was planned to last 5 years. However, an interim analysis conducted after a median follow-up of 2.4 years showed that the hazard ratio for a tumor recurrence in the ipsilateral breast or a new cancer in the contralateral breast was 0.57 for the women taking letrozole, compared with women in the placebo group.

The estimated 4-year disease-free survival among the 2,575 women taking letrozole was estimated at 93%, compared with 87% among the 2,612 women in the placebo group. Overall estimated 4-year survival was 96% and 94%, respectively. The hazard ratio for death from any cause in the letrozole group as compared with the placebo group was 0.76 (N. Engl. J. Med. 349[19]:1793-1802, 2003).

These findings prompted the study's data and safety monitoring committee to terminate the trial early, publish the results on the New England Journal of Medicine's Web site last month, and offer women in the placebo group the opportunity to switch to letrozole, Dr. Goss of Princess Margaret Hospital, Toronto, and his colleagues said.

Currently, adjuvant therapy with tamoxifen for breast cancer is limited to 5 years because there is evidence associating longer therapy with poorer outcomes. However, there is also evidence that aromatase inhibitors are effective in women with metastatic disease that progresses despite treatment with tamoxifen.

The study was led by the National Cancer Institute of Canada Clinical Trials Group and funded in part by Novartis, which markets letrozole as ...