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Aromasin May Be Effective in Women with Advanced Breast Cancer (dateline January 18, 2004)

A small study shows that the drug Aromasin (genetic name, exemestane) may be effective at treating women with advanced breast cancer. In a recent study, advanced breast cancer patients were given either Aromasin or the standard breast cancer drug, tamoxifen. Patients on Aromasin fared better in terms of disease improvement or stability compared to those who were given tamoxifen. Though the study was not designed to determine whether Aromasin is more effective than tamoxifen, the results show that Aromasin may be a viable option for women with advanced breast cancer.

Aromasin was approved by the U.S. Food and Drug Administration (FDA) in 1999 to treat advanced (metastatic) breast cancer in post-menopausal women. Aromasin works by binding to the body’s aromastase enzyme, an enzyme responsible for producing the hormone, estrogen. Many breast cancer cells depend on estrogen to grow and multiply quickly. Once aromasin has binded to the aromastase enzyme, estrogen cannot be produced by the enzyme. This lack of estrogen "starves" cancer cells, preventing them from growing. Aromasin is usually taken orally in pill form.

To study whether Aromasin is effective as a first drug option for women with advanced breast cancer, Dr. Robert Paridaens of the Universitair Ziekenhuis in Leuven, Belgium and his colleagues treated 120 post-menopausal women with advanced breast cancer with daily doses of exemestane (25 milligrams) or tamoxifen (20 milligrams).

The researchers found that 41% of women treated with exemestane saw improvement in their disease, compared to 17% of women treated with tamoxifen. In addition, breast cancer either improved or stabilized for at least six months in 57% of women treated with exemestane compared to 42% treated with tamoxifen.

Possible side effects of Aromasin include:

  • Hot flashes
  • Nausea
  • Fatigue
  • Increased sweating
  • Increased appetite

Larger clinical trials are needed to further determine whether Aromasin is appropriate as a first drug option for advanced breast cancer patients.

Additional Resources and References

  • The report, "Mature Results of a Randomized Phase II Multicenter Study of Exemestane Versus Tamoxifen as First-Line Hormone Therapy for Postmenopausal Women with Metastatic Breast Cancer," is published in the Annals of Oncology (14:1391-1398, 2003),
  • To learn more about drugs used to treat breast cancer, please visit