A multicenter study of 821 patients referred for
breast biopsy based on prior examinations that suggested
cancer finds that while magnetic resonance imaging
distinguishes between benign and malignant breast tumors
better than mammography, biopsies are still needed to
confirm the diagnosis.
The study, called the International Breast MR
Consortium, was carried out in 14 university hospitals in
the United States and Europe, including Johns Hopkins, from
June 1998 through October 2001. All patients underwent MRI
exams prior to breast biopsy.
David Bluemke, associate professor of
radiology in the
Johns Hopkins School of Medicine, led the Hopkins team that
examined 200 of the 821 patients enrolled in the study and
reviewed data from all study participants. MRI correctly
detected cancer in 356 of 404 cancer cases, resulting in a
sensitivity of 88.1 percent. It correctly identified as
negative for cancer 281 of 417 cases without cancer,
producing a specificity rate of 67.7 percent, compared to
52.8 percent for mammography.
While MRI was good at finding cancer, it was less
effective in ruling out malignancies, Bluemke said. "People
who have an abnormal mammogram need to have biopsies of
suspicious lesions," he said. "While MRI aids in
determining the extent of the cancer, it is not a
substitute for breast biopsy. Importantly, however, the MRI
was not adversely affected by factors such as breast
density, tumor type or menopausal status, which frequently
complicates mammographic interpretations."
Bluemke believes MRI will be most beneficial for
patients with difficult-to-interpret mammograms.
The study, funded by the National Cancer Institute, is
published in the Dec. 8 issue of the Journal of the
American Medical Association.
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