WEDNESDAY, July 12, 2006 (HealthDay News) -- An osteoporosis drug now known to help prevent breast cancer does not raise a woman's risk of coronary heart disease, a new study finds.
But the drug, raloxifene (Evista), did increase the risks of blood clots and fatal strokes in women who had already had coronary heart disease or were at high risk for it.
"What it adds to the puzzle for postmenopausal therapies to prevent chronic diseases is that we have to weigh the risks and benefits, and we have to understand that it's not a one-size-fits-all approach," said Dr. Lori Mosca, an investigator for the trial and a physician scientist at New York Presbyterian Hospital in New York City.
"Individual physicians have to look at the risks and benefits of any particular therapy based on an overall assessment of the patient," added Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La. "In a woman who has multiple risk factors for coronary heart disease, or who has already has this, preventing her breast cancer [with raloxifene] may not be the best thing with current drugs that we know work. But for women who are at a low risk, then definitely the advantages far outweigh the disadvantages."
In addition to being widely used as an osteoporosis drug, the recently announced results of the Study of Tamoxifen and Raloxifene (STAR) trial indicate that raloxifene also has a powerful role to play in breast cancer prevention. That study found that raloxifene is as effective as tamoxifen in reducing the risk of invasive breast cancer in postmenopausal women.
The two drugs vary in "side-effect profiles," however, and it hasn't been clear what effect, if any, raloxifene has on the heart.
For the current trial, the Raloxifene Use for The Heart (RUTH) trial, more than 10,000 postmenopausal women with coronary heart disease or risk factors for heart disease were randomly assigned to receive 60 milligrams of raloxifene daily or a placebo. Participants were followed for a median of more than five years.
The trial was funded by Eli Lilly & Co., which makes raloxifene, and the results are published in the July 13 issue of the New England Journal of Medicine.
Compared with placebo, raloxifene has no significant effect on the risk of first-time coronary events. It reduced the risk of invasive breast cancer by 44 percent, translating to 1.2 fewer cancers per 1,000 women treated with raloxifene per year.
While there was no significant difference in the death rates from any cause or total stroke, women in the raloxifene group had a 55 percent increased risk of fatal stroke (0.7 excess fatal stroke per 1,000 women treated per year) and a 44 percent increased risk of blood clots (1.2 more cases per women treated per year).
Raloxifene reduced the risk of vertebral fractures by 35 percent, or 3.7 fewer cases per 1,000 women treated with raloxifene per year.
Unlike the STAR trial, the RUTH trial did not recruit women at high risk for breast cancer, Mosca said. "One could argue that the protective effect is more robust than just in a group at high risk for breast cancer, but we need to put that into the context of an increased risk of fatal stroke and [blood clots]," she added.
But the question is, what level of breast cancer risk justifies using raloxifene, given what is now known about the competing risks?
"I don't think it's a slam-dunk just because raloxifene prevents breast cancer robustly among postmenopausal women," Mosca said. "In our study, there were almost an equal number of risks as there were benefits. It's a very individual decision."
On one level, it comes down to whether women should take a preventive agent for breast cancer at all, she said.
"For postmenopausal women, this could be a very good time to sit down with doctors and really press a discussion about risks for important chronic diseases," Mosca advised. "What's so unique about breast cancer vs. heart disease is that most of the risk for breast cancer is not modifiable, whereas a lot of the risk for heart disease and stroke is. So, the balance of whether or not to take a drug to prevent breast cancer is, I think, a very critical question."
More information
Visit the U.S. National Cancer Institute for more on breast cancer.
