A study released over the weekend at an American Society of Clinical Oncology symposium showed women newly-diagnosed with breast cancer "who receive an MRI after their diagnosis face delays in starting treatment and are more likely to receive a mastectomy." MRI use led to a three week delay in treatment, and, because of the high false positive rate associated with routine MRI use, the breast cancer patients involved were more likely to have a mastectomy.

"Despite lack of evidence of their benefit, the routine use of MRI scans in women newly diagnosed increased significantly between 2004 and 2005, and again in 2006," the study abstract said.