BEIJING, March 28 (Xinhuanet) -- The American Cancer Society is issuing new guidelines that urge annual MRIs (magnetic resonance imaging) for women at high risk, according to news report Wednesday.

    More specifically, the guidelines are directed at women without symptoms of breast cancer who are age 30 and older and who have a certain gene mutation; those who have been treated for Hodgkin's disease; or those with a strong family history of the disease.

    As many as 1.6 million U.S. women fall into this high-risk category.

    For these women, the recommendation adds the MRI exam to the standard tools that doctors should use routinely to try to discover breast cancer, marking the most significant change in the cancer society's influential screening guidelines since doctors started recommending annual mammograms.

    Meanwhile, a new medical study is suggesting that all women newly diagnosed with breast cancer should get MRIs, too. The scans revealed instances of cancers in the opposite breast that were missed by ordinary mammograms.

    The New England Journal of Medicine moved up by one day the release of the first large study to evaluate MRIs in women at higher risk. The study of 969 women in 25 centers found that MRIs detected 30 tumors that had been missed earlier, effectively doubling the number of cancers detected.

    "MRI without question can identify cancer that is invisible to the mammogram," said Constance Lehman of the University of Washington in Seattle, who led the study.

    In addition to allowing women to treat more tumors earlier, MRI can also reassure women that their other breast is cancer-free, enabling them to avoid a double mastectomy, an agonizing choice some women make just to be safe.

    (Agencies)