New U.S. breast cancer screening guidelines issued on Monday by a key advisory panel recommend against routine mammograms for women in their 40s, and suggest women aged 50 to 74 should be screened every other year.

The U.S. Preventive Services Task Force, sponsored by the U.S. Agency for Healthcare Research and Quality, commissioned researchers to use computer simulation models to project the results of different screening strategies.

Here is a rundown of the task force's findings and their recommendations.

* The panel found that women who have screening mammograms, an X-ray of the breast, die less frequently of breast cancer, but for women you are aged 40 to 49, the benefits of screening are small when they factored in the harms of false-positives and the worry and cost of extra tests.

* They found for women aged 50 to 74, routine screening every other year instead of every year brought women nearly all of the benefit in terms of saving lives, while cutting the risk of false positives and other harms by half.

* The panel said there is not enough evidence to recommend routine screening for women over age 74.

* The task force also found no evidence that breast exams done by women or her doctor reduces rates of breast cancer deaths. They recommend against teaching women how to do self breast exams.

* The task force said there is not enough evidence to say whether newer types of screening tests -- digital mammography or magnetic resonance imaging or MRI -- are any better than regular film mammograms.

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