In the past few years, radiologists have used MRI in preoperative staging for women with newly diagnosed breast cancer because it detects additional cancer. Nehmat Houssami, MBBS, PhD, and Daniel F. Hayes, MD, questioned the utility of MRI, stating that the modality could do more harm than good, since there is evidence MRI changes surgical management from breast conservation to more radical surgery (CA Cancer J Clin 59:290-302, 2009).
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. Houssami, an associate professor and principal research fellow at the University of Sydney in Australia, and Dr. 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.
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,” Dr. Houssami and Dr. Hayes wrote. “If the technology is truly as beneficial as its proponents claim, then these costs are worth it.”
Commentary
Prior studies in this area suffer from a lack of standardization in terms of the MRI results that were communicated to or utilized by surgeons, said Chris Comstock, MD, a clinical professor at the University of California, San Diego. “Many of the prior studies evaluating preop MRI involved MRIs that were performed at a much lower quality than current practice,” he said.
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. “In addition, most of the studies have some form of selection bias and none were multicenter, prospective and randomized,” he said.
VANTAGE POINT
Impact on patient outcomes remains uncertain
Constance Lehman, MD, PhD
It is important to keep in mind this is a review article and not a new study presenting new data, said Dr. Lehman, director of imaging at the Seattle Cancer Care Alliance.
“Breast MRI is known to find additional disease in the pre-operative setting, but the impact that improved diagnostic accuracy has on patient outcomes is still unclear. More research is needed for clarification,” she said.
“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.” It’s very easy for a benign lesion to appear malignant on MRI, which underscores the importance of image-guided needle biopsies, explained Dr. Lehman, who is also section head of breast imaging at the University of Washington. “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. Patients should understand that an abnormal MRI should not lead to a premature decision for mastectomy before the true extent of disease is clear.”
Dr. Lehman pointed out that the majority of preoperative breast MRI studies to date have been retrospective and small. The one prospective randomized trial has yet to be published in a peer-reviewed journal, she said. “It is premature to have strong conclusions based on the MRI research in the preoperative setting at this time. The questions raised in the review article are important, but the strength of the authors’ convictions is discordant with the sparse research data on outcomes.”
