The news is good; we need to get the word out.
The mature results of the STAR trial presented at this meeting demonstrate the durability of the therapeutic benefit and the long-term safety of these two agents, and clarify some of the differences and similarities. Despite these compelling results, selective estrogen receptor modulators (SERMs) remain largely underutilized for prevention purposes. So the challenge today is how to communicate to the public to enhance the utilization of SERMs and reduce further the incidence of breast cancer.
There is minimal use of these two drugs by women at risk for breast cancer. In clinical practice, data suggest that only 5%-20% of women who were eligible for these randomized trials agreed to take a SERM for risk reduction. Based on recent reports, this number has only declined.
The picture is similar for raloxifene, with use starting to fall after the release of data regarding toxicity of hormone replacement therapy from the Women's Health Initiative study. The use of raloxifene has continued to fall, in part because of the growing use of bisphosphonates for osteoporosis. Raloxifene has also likely suffered from association with tamoxifen, which is perceived by the public as a toxic cancer drug.
I have to ask, why aren't the results of the BCPT and STAR trials more vigorously applied in clinical practice?
Concerns about adverse events have largely been exaggerated in the public eye by the media. Admittedly, there are also concerns in some quarters about risk prediction models, which only modestly enrich populations for chemoprevention.
There has also been insufficient education of physicians and the public about these drugs. The randomized trials were primarily performed by oncologists, but the application of SERM prevention falls largely on the primary care community, which cares for patients at risk for breast cancer. One would think that instead of neglecting to use both agents, candidates for risk reduction would be pleased to have two good options. There are very good reasons to use these two drugs for cancer prevention. The magnitude of risk reduction with tamoxifen and raloxifene is major--larger than those for many other prevention strategies. In fact, the only intervention of greater preventive efficacy in breast cancer is bilateral prophylactic mastectomy In addition, the safety profiles of these two agents are excellent. Millions of women have taken tamoxifen over the past 3 decades; hundreds of thousands have taken raloxifene over the past 12 years.
There is no perfect drug. Certainly in other areas of preventive medicine, there seems to be greater tolerance for adverse effects for effective preventive interventions. For example, drugs used to treat hypertension and lower cholesterol, both markers of coronary artery disease, have more adverse effects--and more serious ones--than SERMs do. Yet millions of men and women take these drugs daily and for a lifetime.
For a practicing medical oncologist, the adverse effects of SERMs pale in comparison to the complications of and disability caused by breast cancer and the hundreds of thousands of women who die each year worldwide as a result of advanced breast cancer.
GABRIEL N. HORTOBAGYI, M.D., is the director of the breast cancer research program at the University of Texas M.D. Anderson Cancer Center in Houston. He reported he had no conflicts of interest.
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|Author:||Hortobagyi, Gabriel N.|
|Publication:||OB GYN News|
|Date:||May 1, 2010|
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