WASHINGTON, April 19 (UPI) -- A long-term study of almost 20,000 women indicates two drugs -- raloxifene and tamoxifen -- are effective in breast cancer cases, U.S. researchers said.
The osteoporosis drug raloxifene, or Evista, was effective in non-invasive breast cancer and slightly less effective against invasive breast cancer, the study said.
The study also found raloxifene caused significantly less endometrial cancer and was less toxic than the other drug tested -- tamoxifen.
Tamoxifen reduces the risk of breast cancer but can increase the risk of endometrial cancer and can cause hot flashes and other symptoms, so many at-risk women have chosen not to take the drug, researchers said.
Study co-author Patricia Ganz of the University of California, Los Angeles, says the study found raloxifene doesn't substantially increase the risk of endometrial cancer.
A typical U.S. woman has about a 12 percent risk of getting breast cancer, but that risk increases to 18 percent if a woman's mother or sister had breast cancer and 30 percent for a woman with a breast lesion -- atypical hyperplasia, Ganz told USA Today.
The findings were presented at the American Association for Cancer Research 101st annual meeting during a special plenary session Monday in Washington. These results are also published in the journal Cancer Prevention Research.