Letrozole tops tamoxifen for early breast cancer
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.
In the current analysis of the data, reported in Thursday’s New England Journal of Medicine, the researchers focused on the drugs that the women were treated with initially. Therefore, women who received letrozole initially were compared with those who received tamoxifen initially.
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.
Swain, from the National Cancer Institute in Bethesda, Maryland, adds that longer follow-up from several ongoing studies is needed “to enable us to offer patients sound advice regarding the benefits and long-term risks of aromatase inhibitors.”
SOURCE: New England Journal of Medicine, December 28, 2005.
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