A study in the New England Journal of Medicine shows that a class of drugs to block estrogen is highly successful in preventing recurrence of breast cancer. Women who have had breast cancer are always at risk for recurrence. The female hormone, estrogen, has to attach to breast cells on special hooks called estrogen receptors, before it can stimulate breast cells to grow. Doctors routinely prescribe the drug, Tamoxifen, to attach to these receptors to prevent estrogen from attaching to them and stimulating breast cancer cells to grow. However, after five years, Tamoxifen often stops doing its job.

The authors of this study gave these women, who had had Tamoxifen, a new drug called Femara, made by Novartis, and it halved the risk of breast cancer returning. The results were so dramatic, that the doctors felt morally responsible to stop the study and offer Femara to all the women in the study. Doctors still do not know how long to prescribe Femara or its long-term toxic effects. Femara, also known as letrozole suppresses production of estrogen. Side effects include osteoporosis, hot flashes, night sweats and bone pain.

New England Journal of Medicine , November 6, 2003

Checked 9/3/05

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