NEW YORK (Reuters Health) - In a new clinical practice guideline, the American College of Physicians (ACP) recommends that decisions regarding mammography screening for women aged 40 to 49 should be made on a case-by-case basis, taking into account each patient's preferences and risk profile.

Dr. Amir Qaseem, with the Philadelphia-based ACP, and his associates developed four recommendations, which are published in the Annals of Internal Medicine for April 3. The new guideline is based on a systematic review, published in the same issue of the journal.

The ACP first urges clinicians to periodically assess a woman's risk for breast cancer.

According to the second recommendation, clinicians need to inform women in their 40s about the potential risks and benefits of screening mammography.

The third recommends that decisions about screening should be based on the benefit and harms of screening, the patient's breast cancer risk profile, and her own preferences.

The fourth recommendation is a call for high-quality trials to confirm the effectiveness of screening in this age group.

In the second paper, Dr. Katrina Armstrong, from the University of Pennsylvania in Philadelphia, and her team review findings from eight meta-analyses, plus 117 related articles identified through a literature search. Their goal was "to evaluate the evidence about the risks and benefits of mammography screening for women in their 40s."

The meta-analyses revealed a 7% to 23% decrease in breast cancer mortality among women in their 40s who underwent mammography. Most studies put the proportion of false-positive test results at 2% and 4%, Dr. Armstrong and her associates report.

The risk from radiation is small, the authors write. Furthermore, most women experience some pain during mammography, but they do not consider it a barrier to undergoing future mammograms. For most women informed of false-positive test results, any related anxiety and depression resolves quickly, and subsequent mammography adherence is not affected.

The researchers found that, for some women in their 40s, the risks of mammography may outweigh the benefits, suggesting that they can safely postpone screening.

With regards to the guideline's demand for future, high-quality trials, this level of research is not feasible, Drs. Joann G. Elmore and John H. Choe write in an accompanying editorial. Instead, they insist that physicians need to "learn to become comfortable with using the art of medicine to translate the existing science."

"We must listen carefully to our patients and communicate honestly the benefits and limitations of our imperfect tests," note Drs. Elmore and Choe, both from the University of Washington, Seattle.