Arimidex, the new preparation, reduces the risk of breast cancer development by more than half among postmenopausal women at high risk for the disease, according to a new study.

"Two other antihormone therapies, tamoxifen and raloxifene, are used by some women to prevent breast cancer, but these drugs are not as effective and can have adverse side effects, which limit their use," study lead author Jack Cuzick said in a new release from the American Association for Cancer Research, Newsmax Health reports.

 "Hopefully, our findings will lead to an alternative prevention therapy with fewer side effects for postmenopausal women at high risk for developing breast cancer," said Cuzick, head of the Cancer Research U.K. Centre for Cancer Prevention and director of the Wolfson Institute of Preventive Medicine at Queen Mary University of London.

 About 80 percent of U.S. breast cancer patients have tumors with high levels of hormone receptors, and these tumors are fueled by the hormone estrogen. Arimidex prevents the body from making estrogen and is therefore used to treat postmenopausal women with hormone receptor-positive breast cancer.

 The study included more than 3,800 postmenopausal women at increased risk for breast cancer due to having two or more blood relatives with breast cancer, having a mother or sister who developed breast cancer before age 50.

 About half the women took Arimidex for five years while the others took a placebo, or dummy drug. Those who took the drug were 53 percent less likely to develop breast cancer than those who took the placebo. Side effects among the women taking the drug included hot flashes and small increases in muscle aches and pains.