Breast cancer prevention drug raises fatal stroke risk

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Breast cancer prevention drug raises fatal stroke risk

Breast cancer prevention as powerful with raloxifene as with tamoxifen — but both carry risks.

What happened? A new study confirmed that the osteoporosis drug raloxifene reduces the risk of invasive breast cancer in postmenopausal women — but women with cardiac risk factors or history of heart disease need to weigh the benefits against an increased risk of blood clots and fatal stroke.

The finding, from the Raloxifene Use for the Heart (RUTH) clinical trial, sounded a cautionary note following recently published positive results from the Study of Tamoxifen and Raloxifene (STAR) trial. The STAR trial found that raloxifene and the established breast cancer prevention drug tamoxifen were equally effective in preventing invasive breast cancer in high-risk postmenopausal women.

The RUTH trial involved more than 10,000 women with known history of heart disease or increased risk of heart attacks and strokes. Roughly half the women were treated with raloxifene, while the other half received a placebo.

After five to six years of follow-up, the two groups showed no difference in rates of heart attacks and nonfatal strokes. But the risk of fatal stroke was increased by 49 percent in the women taking raloxifene, 59 of whom died of strokes, as compared with 39 in the placebo group. The risk of blood clots was also higher in the raloxifene group.

What does this mean to you? If you're postmenopausal and at increased risk of breast cancer, raloxifene may still be a good choice for you — but first, talk to your doctor if you have a history of heart disease or multiple cardiac risk factors.

These risk factors include smoking, high blood pressure, high cholesterol and diabetes. It's important to consider whether the breast cancer prevention benefit outweighs the stroke and blood clot risks in your case.

Tamoxifen, which is approved by the Food and Drug Administration (FDA) for reducing the risk of breast cancer, is another option if you are increased risk of breast cancer. With tamoxifen, too, the risks and benefits vary among individuals, based on family history, degree of breast cancer risk and medical history.

If you're premenopausal and at increased risk of breast cancer, these study results have no immediate bearing on you. Tamoxifen continues to be an option for reducing your breast cancer risk. Discuss the risks and benefits to determine if tamoxifen is appropriate based on your individual breast cancer risk.

Last Updated: 07/17/2006
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