Anastrozole Halves Breast Cancer Risk in Older Women: Study

Daily use of Anastrozole- a breast cancer drug- could potentially save lives of thousands of women. A latest study has shown that regular use of the drug for five years reduces breast cancer risk by 53 percent in postmenopausal women who have high chances of breast cancer.

The finding could offer a new way of cutting breast cancer risk in older women.

Anastrozole belongs to a class of medications called nonsteroidal aromatase inhibitors and works by decreasing the amount of female hormone estrogen produced by the body. The drug is usually prescribed to menopausal women diagnosed with early-stage breast cancer. Anastrozole is also given to women whose breast cancer that has spread to other parts of the body or has gotten worse due to the use of standard breast cancer drug tamoxifen (Nolvadex).

The study was conducted by researchers at Queen Mary University of London and colleagues.

 "This research is an exciting development in breast cancer prevention.  We now know anastrozole should be the drug of choice when it comes to reducing the risk of breast cancer in postmenopausal women with a family history or other risk factors for the disease. This class of drugs is more effective than previous drugs such as tamoxifen and crucially, it has fewer side effects," Professor Jack Cuzick, lead researcher and head of Queen Mary University of London's Centre for Cancer Prevention, said in a news release.

The study was based on data from 4,000 postmenopausal women who had high risk of developing breast cancer. The participants were randomly divided into two groups, with one group receiving a daily 1mg dose of anastrozole and the other getting a placebo. After five years, about 85 women in the control group developed breast cancer compared to 40 women in the anastrozole group.

Breast cancer is one of the leading causes of deaths in the U.S.  Earlier research has linked genetics, hormones, stress and environmental toxins to breast cancer risk. In the present study, participants were classified as high-risk for breast cancer if they fulfilled certain criteria such as having a close relative (mother, sister) who developed the cancer before age 50, having a benign breast cancer.

Only future research can tell if the medication is safe to use as a preventive drug to reduce breast cancer risk. The study was funded by the Cancer Research UK.

 "This landmark study shows that anastrozole could be valuable in helping to prevent breast cancer in women at higher than average risk of disease. We now need accurate tests that will predict which women will most benefit from anastrozole and those who will have the fewest side-effects," Kate Law, director of clinical research at Cancer Research UK.

The study was published in the journal The Lancet.                                                                                                 

Anastrozole could lead to weak bones and worsen osteoporosis, according to Medline Plus. Very rarely, the drug might cause blood clots. The drug was first approved by FDA in 1995.