Studies Say Drugs May Prevent, Slow Spread of Breast Cancer

The newly FDA-approved osteoporosis drug raloxifene may greatly reduce post-menopausal women’s risk for breast cancer, according to several studies of the drug. Doctors and researchers will release extensive data on the drug today at an American Society of Clinical Oncology (ASCO) conference in Los Angeles.

In studies originally designed to test the drug’s effects on osteoporosis, women who were administered raloxifene reduced their risk for breast cancer by 70% compared to women who were given placebo pills. “To see a 70 percent overall reduction in risk is astounding,” said Steven Cummings, a medicine and epidemiology professor at U-California, San-Francisco and co-lead author of the study.

Before raloxifene, tamoxifen was the only drug believed to reduce the risk of breast cancer. Unlike tamoxifen, raloxifene does not increase women’s risk of developing endometrial cancer.

In another study, a drug called herceptin was found to slow the spread of breast cancer and limit tumor growth in women whose cancer has metastasized, or spread from the original tumor to another part of the body.

The drug has been tested in three phases of clinical trials and may be eligible for FDA approval soon. Herceptin works by blocking production of a protein called HER2/neu. Genetic defects cause about 25-30 percent of breast cancer patients to produce too much of this protein. These patients have a life-expectancy of only 10-18 months once the cancer has metastasized, or spread from the original tumor.

Herceptin does not cause the hair loss and decreased blood counts that follow traditional chemotherapy and can boost the positive effects of chemotherapy drugs by fifty percent when the two are administered jointly.

Critics warn that the media hype over raloxifene, herceptin and other so-called “miracle” drugs may be unwarranted, and that further studies are needed to confirm both the positive and negative effects of these drugs. Fran Visco, president of the National Breast Cancer Coalition in Washington D.C., told the Washington Post that she is “very disturbed” about the media hype around raloxifene, arguing that a few years’ worth of data cannot possibly track the development of breast or endometrial cancer. “The idea that there is a single pathway in every cancer and if you just fix that one pathway you will cure all cancer is fanciful and experience tells us that is unrealistic,” said Dr. Allen Lichter, president-elect of ASCO.


Reuters and Washington Post - May 17-18, 1998

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