Women with a recent diagnosis of cancer in one breast should have MRI screening of the opposite breast, concludes a multi-center study involving University of North Carolina at Chapel Hill researchers.

The international research team found that MRI, or magnetic resonance imaging, detected cancer in the opposite breast in 30 of 969 women (3.1 percent) who had recently been diagnosed with cancer in one breast only. The cancers in the opposite breast were missed by previous mammography and clinical exam.

The authors recommend MRI screening for women at high risk for breast cancer - those who already have the disease, have been recently diagnosed or have a family history of breast cancer. The results appear in The New England Journal of Medicine.

"This study is pretty definitive evidence that the opposite breast needs to be evaluated with MRI," said study co-author Dr. Etta Pisano, a principal investigator and Kenan professor of radiology and biomedical engineering at the UNC School of Medicine. "But no one is recommending that we give up mammography. MRI screening is a very expensive tool that should be used judiciously for high risk populations. The last thing we would want is for every woman to think she should get an MRI," Pisano said.