Letrozole tops tamoxifen for early breast cancer

NEW YORK (Reuters Health) - As add-on therapy for breast cancer, letrozole appears to be more effective than tamoxifen in reducing the risk of the disease recurring, new research suggests.

Dr. Beat Thurlimann, from the Senology Center of Eastern Switzerland in Kantonsspital, and colleagues compared the outcomes of 8010 women who were randomly assigned to one of four treatment regimens for 5 years: letrozole; letrozole followed by tamoxifen; tamoxifen; or tamoxifen followed by letrozole.

During an average follow-up period of just over 2 years, a total of 351 cancer recurrences were noted in the letrozole group, while 428 occurred in the tamoxifen group. Compared with tamoxifen, letrozole cut the risk of recurrent disease by 19 percent, the report indicates.

Treatment with tamoxifen was associated with higher rates of blood clots, endometrial cancer, and vaginal bleeding. On the other hand, letrozole therapy was tied to higher rates of skeletal and heart problems, as well as high cholesterol levels.

The study was supported by Novartis Pharmaceuticals Corp., which markets letrozole as Femara.

Letrozole is in a class of drugs known as aromatase inhibitors. The new findings "validate the results of previous studies showing that aromatase inhibitors were more efficacious than tamoxifen" in postmenopausal women with early-stage breast cancer, Dr. Sandra M. Swain comments in a related editorial.

SOURCE: New England Journal of Medicine, December 28, 2005