Prostate Cancer Drugs May Pose Danger
Study Finds Common Therapy Might Increase Risks of Heart Disease, Diabetes

By Rob Stein
Washington Post Staff Writer
Tuesday, September 19, 2006

Drugs commonly used to treat prostate cancer may increase the risk of heart disease and diabetes, indicating the treatments should be used more judiciously, researchers reported yesterday.

The findings apply to thousands of American men because prostate cancer is the second-most-common cancer in males (after skin cancer) and because the drugs have become standard therapy.

"Our study is the first to show there may be this increased risk," said Nancy L. Keating of Harvard Medical School, who led the study being published in tomorrow's issue of the Journal of Clinical Oncology.

Prostate cancer strikes about 234,000 men each year in the United States and kills more than 27,000. The disease is usually treated with surgery, radiation and -- in men whose cancer has spread -- drugs that block the hormone testosterone.

These drugs, called known as gonadotropin-releasing hormone (GnRH) agonists, have clear benefits for men whose cancer has spread. Their value in less advanced cases is not as clear, but doctors are increasingly using the drugs in these cases as well. Some earlier studies had suggested, however, that the drugs increased weight gain around the abdomen and resistance to insulin, which controls blood sugar levels.

To investigate whether that may increase the risk of heart disease and diabetes, researchers analyzed data collected in the 1990s from more than 70,000 men with prostate cancer that had not spread or had just begun to spread, and then followed them until 2001 or 2002.

Men who were getting one of the drugs were 44 percent more likely to develop diabetes, 16 percent more likely to develop heart disease and 11 percent more likely to have a heart attack or die suddenly from heart failure, the researchers found.

"Given the number of people on these drugs and the fact that some of these men may not necessarily be getting any benefit, I think it's a bit concerning," Keating said. "What this means is that doctors and their patients really need to think about these risks and think about why they are really on these drugs."

Keating stressed that the drugs clearly have a benefit for men with advanced prostate cancer that has spread, and for some men with locally advanced cancer.

But in other cases, Keating said, "I think we should more cautious about prescribing these drugs."

Other experts said more research is needed to confirm and explore the results.

"These data raise the possibility these agents may have these risks," said Lori Minasian of the National Cancer Institute. "But I don't think the data raise to the level yet where men should not take hormone therapy."

Although the researchers tried to consider other factors that could account for the findings, it is possible that men in the study who received hormone therapy had other risk factors that predisposed them to heart disease and diabetes, Minasian and other experts said.

"It could be that these men tend to be unhealthier men," said Christopher Amling of the University of Alabama at Birmingham, a spokesman for the American Urological Association.

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