HOUSTON -

New research suggests doctors should add a pill to the list of options for women to lower their risk for breast cancer.

Women who have a strong family history of breast cancer may benefit from a new drug.

"There are millions of women who could benefit from a drug such as Anastrozole in reducing the risk of ever developing breast cancer," said Dr. Therese Bevers of the MD Anderson Cancer Center.

In a study of nearly 4,000 high risk, post-menopausal women, those who took Anastrozole for five years were half as likely to develop breast cancer than women on a placebo.

while this included invasive tumors, there was no difference in overall mortality rates.

Experts say this is an important addition to medications women already have for preventing cancer, and maybe more effective than Tamoxifen, with fewer side effects.

"Some of the side effects that were seen with anastrozole in this trial were largely musculoskeletal problems and hot flashes; however these were really quite rare," Bevers said.

In the study, Anastrozole cut the incidence of breast cancers from four to two percent over five years.

It works by preventing the body from making Estrogen, the fuel for many breast cancers.

The drug is available in generic form, which could make it cheaper. It's been used for years to treat some women already diagnosed with the disease in the US.