In the Fight Against Breast Cancer, Letrozole Outperforms Tamoxifen

Older women diagnosed with hormone-sensitive breast cancer are more likely to live longer and less likely to experience cancer recurrence when treated with the drug Femara (letrozole) as opposed to tamoxifen, a long-term follow-up study published online October 21 in The Lancet Oncology shows.

In the study, researchers updated data from the previously published study by the Breast International Group, an analysis of approximately 8000 postmenopausal women from 27 countries. The participants previously underwent surgery for cancer that had not metastasized beyond the breasts and lymph nodes.

The study compared the 2 drugs prescribed alone as well as the use of letrozole and tamoxifen consecutively:

• One group of patients took either tamoxifen or letrozole for 5 years
• A second group took either tamoxifen for 2 years followed by 3 years of letrozole or 2 years of letrozole followed by 3 years of tamoxifen

Researchers found letrozole performed better than tamoxifen in terms of breast cancer recurrence and patient survival. Neither consecutive treatment of tamoxifen followed by letrozole, nor the reverse order, was more effective than treating women with letrozole alone.

More specifically, after an average 8 years of follow-up, the team of researchers from the United States, Europe, and Australia found that women who took letrozole for 5 years after surgery were 20% less likely to experience breast cancer recurrence and 21% less likely to die of their breast cancer compared with postmenopausal women who took tamoxifen.

This updated analysis shows that, for postmenopausal women with estrogen-dependent tumors, aromatase inhibitors may be a more effective treatment option than tamoxifen.

Source: The Lancet Oncology.