TODAY | December 06, 2012
>>> and a new study out of oxford recommends that breast cancer patients who use the drug tomoxifin stay on it twice as long as doctors recommend.
>> reporter: the studies should improve the outlook for hundreds of thousands of breast cancer survivors, including emily who takes a common estrogen blocking drug. researchers found that women who take tamoxifen for five years had a third less chance of dying from the disease. but the risk was cut in half if they took the drug for ten.
>> it's significant. it couldn't be a chance finding. the study had nearly 7,000 women from 36 countries. and so it's based on big numbers .
>> reporter: 3/4 of women with breast cancer , her tumor was estrogen positive, meaning it is fueled by the female hormone. after surgery and radiation, doctors put her on tamoxifen to reduce the chances of the cancer coming back. in the united states , women past menopause usually get more powerful inhibitors, but the doctors say the results mean that all women with estrogen positive tumors should probably be getting some drug for at least ten years. she is fine with her treatment continuing.
>> cancer is something i think about every day and just keep taking it would be fine with me.
>> tamoxifen has possible side effects from hot flashes to blood clots and increased risk in endometrio cancer. for today, nbc news, san antonio .