Osteoporosis Drug May Prevent Breast Cancer.
Evista Protective Regardless of Previous Hormone Use
WebMD News Archive
Nov. 2, 2004 (Vienna, Austria) -- The bone-protecting drug Evista has a cancer-protective effect regardless of whether a woman has previously taken hormone replacement therapy (HRT), British researchers report.
Many postmenopausal women who are prescribed Evista to prevent or treat osteoporosis have previously taken HRT, which carries an increased risk of breast cancer, says Trevor Powles, MD, emeritus professor of breast oncology at the Institute of Cancer Research in London.
The new study was designed to determine whether this HRT use could have decreased the subsequent value of Evista in reducing the risk of breast cancer, he said at the annual meeting of the European Society for Medical Oncology.
In what Powles terms "reassuring findings," the study showed that compared with a placebo, Evista cut the risk of developing invasive breast cancer by about two-thirds regardless of whether a woman had taken HRT. The study was sponsored by Evista manufacturer Eli Lilly and Co., a WebMD sponsor.
Is Evista Better Than Tamoxifen?
The researchers studied more than 7,000 postmenopausal women with osteoporosis; more than 5,000 were prescribed Evista and the rest, a placebo. About a third of the women reported they had also taken hormone replacement therapy.
Jan B. Vermorken, MD, press officer for the European Society for Medical Oncology and professor of oncology at the University of Antwerp in Belgium, says the study provides convincing evidence that Evista reduces the risk of breast cancer among postmenopausal women.
"The total number of patients studied is more than 7,000," he tells WebMD. "That kind of number carries a lot of power."
Despite the promising data, both he and Powles stress that Evista is still only approved for use in preventing and treating osteoporosis. The only drug approved for prevention of breast cancer is tamoxifen.
Also, although Evista has few side effects, it does carry a small increased risk for blood clots, especially clots in the legs, Powles says.
But tamoxifen carries risks of its own, chiefly that of endometrial cancer, says Jose Baselga, MD, chairman of the department of oncology at Vall D'Hebron University Hospital in Barcelona, Spain. While tamoxifen and Evista both protect against breast cancer, Evista "could play a better role as a preventive because it is devoid of this side effect," he says.