Can Breast MRI Help Evaluate Cancer?
Study Weighs the Benefits, Risks of Routine Breast MRIs for Cancer Evaluation
Sept. 8, 2008 -- Routine use of breast MRI
(magnetic resonance imaging) scans to help evaluate cancer after diagnosis is not
as beneficial as some believed, according to a new study.
"The bottom line is it doesn't help us as much as we thought it
did," says Richard J. Bleicher, MD, a surgical oncologist at Fox Chase
Cancer Center in Philadelphia and lead author of the study, presented Saturday
at the American Society of Clinical Oncology Breast Cancer Symposium in
But another expert who reviewed the study abstract for WebMD says the study
was small and that the role of breast MRI to evaluate cancer is still
On one point all sides seem to agree: More research is needed to determine
if MRI can improve the outcomes of women with breast cancer.
Bleicher and his colleagues reviewed the records of 577 breast cancer
patients, including 130 who had MRIs before treatment and 447 who did not. The
goal was to determine the effect, if any, of getting an MRI on the time to
start treatment, the chances of removal of all the cancer, and other
"We wanted to ascertain whether routine MRIs [for cancer, not for
screenings] are helpful and do they, in fact, assist us in treatment
planning," Bleicher tells WebMD.
The role of breast MRI for screening, he says, is clearer. The American
Cancer Society, for instance, advises that MRIs be used in combination with
mammograms for preventive screenings of certain women at especially high risk
of breast cancer.
But the role of the breast MRI to evaluate breast cancer is not as clear, he
The thinking among experts, he says, is that MRIs, because they are so
sensitive, may allow better visualization of the cancer, so using one when
cancer is diagnosed or suspected should help guide treatment decisions.
Breast MRI Study Findings
Among the findings:
- Breast MRI was associated with a 22-day delay in the start of treatment.
"We don't know why," Bleicher says. It could be because of the
scheduling of the MRI itself, or perhaps MRI prompts other biopsies." Three
weeks should not change a patient's survival chances, he says, but waiting can
clearly add to a patient's anxiety.
- Those who got the breast MRI were nearly twice as likely to have a mastectomy as breast-conserving surgery, even after
controlling for size and stage of the tumor. One reason, he says, may be that
the MRI, being highly sensitive, picked up something that looked like cancer
but turned out not to be -- a false positive.
- Those who got the breast MRI were slightly more likely to have what
surgeons call positive margins, although this finding could have been a chance
finding. The goal is negative margins. "The goal is to excise out the tumor
so there is a margin of normal tissue around it, reassuring us the cancer has
been completely removed," he says.
- Younger women were more likely than older women to have MRIs, but the use
of the MRI did not correlate with other factors such as family history of
breast or ovarian