Breast cancer drugs raise blood clot risk

PORTLAND, Ore. (UPI) -- Drugs used to lower the risk of breast cancer in women have the side effect of increasing the likelihood of blood clots, researchers in Oregon say. The study, published in the current issue of Annals of Internal Medicine, examined the effects of tamoxifen, raloxifene and tibolone reduce the risk of invasive breast cancer by 30 percent to 68 percent. But it also found tamoxifen and raloxifene increase the chance of blood clots by 60 percent to 90 percent, and that tiboline, which is not on the U.S. market, is associated with strokes in women over 70. "They did differ on the harm side. That's important to know," said Dr. Heidi D. Nelson, a research professor at Oregon Health & Science University who was the lead author. Copyright 2009 by United Press International