TUESDAY, Feb. 22 (HealthDay News) -- Radiologists who interpret large numbers of mammograms may not detect more breast cancers, but are better at identifying breast lesions that are not cancerous, a new study finds.

Researchers examined the performance of 120 radiologists in six states (California, North Carolina, New Hampshire, Vermont, Washington and New Mexico) who interpreted nearly 800,000 screening mammograms between 2002 and 2006.

Contrary to their expectations, the researchers found no clear association between the number of mammograms interpreted by a radiologist and the ability to identify cancers.

"We did, however, find that radiologists with higher interpretive volume had significantly lower false-positive rates and recalled fewer women per cancer detected," lead author Diana S.M. Buist, senior investigator at the Group Health Research Institute in Seattle, said in a Radiological Society of North America news release.

A false-positive result occurs when further testing is recommended for a suspicious lesion but no cancer is found. False-positive results cause anxiety for patients and lead to additional tests that cost about $1.6 billion a year in the United States, Buist said.

The study also found a link between a radiologist's mammogram screening ability and the ratio of screening to total (diagnostic plus screening) mammograms.

"The data suggest that radiologists who interpret screening mammograms should spend at least a portion of their time interpreting diagnostic mammograms, because radiologists who interpreted very few diagnostic mammograms had worse performance, even if they read a high volume of screening mammograms," Buist said.

She and her colleagues also calculated the effect of increasing the minimum interpretive volume required of U.S. radiologists, which is currently 960 mammograms every two years.

Increasing the annual minimum total volume to 1,000 would result in 43,629 fewer women being recalled for further tests, the researchers estimated.

The study appears online and in the April print issue of Radiology.

More information

The National Cancer Institute has more about breast cancer screening.