Experts contest article declaring breast MRI may cause more harm than good

August 19, 2009

A review article asserting breast MRI does not improve surgical planning, reduce follow-up surgeries, or reduce the risk of local recurrences is drawing fire in the breast imaging community.

A review article asserting breast MRI does not improve surgical planning, reduce follow-up surgeries, or reduce the risk of local recurrences is drawing fire in the breast imaging community.

In the past few years, radiologists have used MRI in preoperative staging for women with newly diagnosed breast cancer because it detects additional cancer.

The recent review article questions the utility of MRI and says the modality may cause more harm than good, since there is evidence MRI changes surgical management from breast conservation to more radical surgery (CA Cancer J Clin 2009;59:epub ahead of print).

Using MRI led to 11.3% of patients having more extensive surgery than initially planned, either mastectomy or wider resection of the preserved breast, according to Dr. Nehmat Houssami, an associate professor and principal research fellow at the University of Sydney in Australia, and Dr. Daniel F. Hayes, clinical director of the breast oncology program at the University of Michigan Comprehensive Cancer Center in Ann Arbor.

"Overall there is growing evidence that MRI does not improve surgical care, and it could be argued that it has a potentially harmful effect," the researchers said.

It's important to keep in mind this is a review article, not a new study presenting new data, said Dr. Constance Lehman, the head of breast imaging at the University of Washington in Seattle.

Breast MRI is known to find additional disease in the preoperative setting, according to Lehman. The impact the improved diagnostic accuracy has on patient outcomes is still unclear. More research is needed for clarification.

"In the absence of clear data, many have strong opinions. At this time, centers whose physicians have experienced benefits of the improved diagnostic accuracy of MRI in their patients will likely continue to use breast MRI, while those who have had poor outcomes will not continue until the issues are more clear," she said.

It's very easy for a benign lesion to appear malignant on MRI, which underscores the importance of image-guided needle biopsies, she said. A radiologist never wants to rely solely on an MRI to determine preoperative staging and should always have tissue confirmation to ensure patients receive the proper care.

Another criticism of the review article is the type of evidence used: at this time the majority of the studies are retrospective and relatively small, according to Lehman.

"Many of the prior studies evaluating pre-op MRI involved MRIs that were performed at a much lower quality than current practice," said Dr. Chris Comstock, a clinical professor at the University of California, San Diego.

For instance, most current studies have a voxel size of 1 mm or less. Many of the older studies included in this review used MRIs with a slice thickness greater than 3 mm, so the specificity is going to be less, he said.

"In addition, most of the studies have some form of selection bias and none were multicenter, prospective and randomized," he said.

To know whether preoperative MRI is useful will require large-scale, multicenter, prospective trials.

"We acknowledge that logistics and costs of conducting such large-scale, multicenter trials are enormous," Houssami and Hayes wrote. "If the technology is truly as beneficial as its proponents claim, then these costs are worth it."