Femara Superior to Tamoxifen Study Shows

Aromatase inhibitor letrozole reduces breast cancer relapses and deaths

(RxWiki News) For years, tamoxifen  has been the gold standard for keeping breast cancer from reappearing. Updated research shows another medication known as an aromatase inhibitor is even more effective for post-menopausal women.

In the longest follow-up trial  comparing tamoxifen with Femara (letrozole), researchers have found that the aromatase inhitibor (AI) letrozole is superior in preventing relapses and reducing the risks of death in post-menopausal women diagnosed with early stage hormone driven breast cancer.

"Femara may work better than tamoxifen in post-menopausal women."

Findings from the 12-year update of of the Breast International Group (BIG) 1-98 trial, found that women who took Femara for at least five years following breast cancer surgery fared better and had fewer relapses than women taking tamoxifen.

According to Professor Richard Gelber, director of the International BreastCancer Study Group (IBCSG) Statistical and Data Management Center at the Dana-Farber Cancer Institute, women taking letrozole had an 18 percent reduced risk of recurrence and a 21 percent reduced risk of death compared to women taking tamoxifen.

Femara and tamoxifen are called adjuvant therapies; they are treatments given after surgery. They both block hormones - primarily estrogen - in patients who have hormone receptor-positive cancers, which account for 75 percent of all breast cancers.

Gelber points out that the recent update has gathered more results since the 10-year update and demonstrates that "overall survival advantage for adjuvant letrozole compared to tamoxifen continues to be statistically significant."

The BIG 1-98 trial involved 8,010 patients who received letrozole and tamoxifen either alone or in sequence, with a total of 4,922 patients who received a monotherapy only. Analyses of efficicacy were conducted every two years.

Gelber says more study is needed to determine the long-term safety of letrozole. The BIG 1-98 observational study will be extended another five years to further analyze the efficacy, sife effects and overall safety of the medication.

Findings from this update were presented September 26th at the 2011 European Multidisciplinary Cancer Congress in Stockholm.

The BIG 1-98 trial was supported by Novartis, the manufacturer of Femara.

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Review Date: 
October 4, 2011