Saturday, June 4, 2011

Breast cancer drug with fewer side effects found to cut risk of tumors


Exemestane, sold under the brand name Aromasin, can reduce the risk of tumors by 65% among menopausal women prone to develop breast cancer, researchers say. It's already used to treat breast cancer and does not appear to have the lethal side effects of tamoxifen or raloxifene.

Exemestane, sold under the brand name Aromasin, provides an even greater reduction in risk and so far does not appear to have those lethal side effects, a team headed by Dr. Paul E. Goss of the Massachusetts General Hospital Cancer Center reported at a Chicago meeting of the American Society of Clinical Oncology and online in the New England Journal of Medicine.

Exemestane thus provides an alternative for women who wish to avoid severe side effects, and some experts predict that the number of women taking prophylactic therapy should increase significantly, particularly since the drug is already on the market for fighting breast cancer and physicians can prescribe it for any purpose they choose.

"Breast cancer is the second most common cause of death from cancer in and one of the most feared diagnoses for women in the United States," Dr. Nancy E. Davidson and Dr. Thomas W. Kensler of the University of Pittsburgh Cancer Institute wrote in an editorial accompanying the report. "We have the knowledge and tools to reduce its incidence today. We have run out of excuses. What are we waiting for?"

But Dr. Joanne Mortimer, director of the Women's Cancers Program at the City of Hope Comprehensive Cancer Center in Duarte noted that, even though all three drugs have been shown to reduce the risk of breast cancer, there is as yet no evidence that they reduce the risk of dying. That is why "most patients opt not to take them," she said.

Many studies have shown that estrogen produced by the body promotes breast tumors. Tamoxifen and raloxifene are so-called anti-estrogens that bind to receptors on the surface of breast tissue cells, preventing estrogen from binding. Exemestane, manufactured by Pfizer Inc., is one of a family of drugs called aromatase inhibitors, which block production of estrogen by the body. Astrazeneca's Arimidex and Novartis' Femara are members of the same family, but have not been tested for cancer prevention.
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