Dr. Richard J. Bleicher, a specialist in breast cancer surgery at Fox Chase Cancer Centre, said that there was no evidence that MRI improved outcomes when used routinely to evaluate breast cancer.
"For most women, an MRI scan prior to treatment is unnecessary. MRI can be of benefit because it's more sensitive, but with the high number of false positives and costs associated with the test, more studies are needed to determine whether MRI can improve outcomes in women with breast cancer," he said.
Bleicher and his colleagues analysed the records of 577 breast cancer patients seen in a multidisciplinary breast clinic where they were evaluated by a radiologist, pathologist, and a surgical, radiation, and medical oncologist.
Of the study subjects, 130 had had MRIs prior to treatment.
"Those who received an MRI had a three-week delay in the start of their treatment," said Bleicher.
"In addition to the treatment delay, we're concerned that the well-documented false-positive rate with MRIs may be leading - or misleading - women into choosing mastectomies," he added.
The study also showed that younger women were more likely to have an MRI.
"In our analysis, that trend didn't correspond with various breast cancer risk factors, such as a family history of breast or ovarian cancer, nor with the characteristics of their disease," said Bleicher.
"MRI is a valuable tool in some women, but without evidence that routine pre-treatment MRI improves a woman's outcome, its disadvantages suggest that it should not be a routine part of patient evaluation for treatment," he added.
The study was presented at the 2008 ASCO Breast Cancer Symposium.