Study Weighs the Benefits, Risks of Routine Breast MRIs for Cancer Evaluation
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Reviewed By Louise Chang, MD
"The bottom line is it doesn't help us 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 Washington, D.C.
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 evolving.
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 outcomes.
"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 says.
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 cancer.
Breast MRI Research Evolving
Another expert, Constance Lehman, MD, PhD, professor and vice chair of radiology and head of breast imaging at the University of Washington Medical Center and director of imaging at the Seattle Cancer Care Alliance, reviewed the study for WebMD. She says the new study is "not the kind of study we need to make firm conclusions."
She points out that the study was small and that only 130 women had breast MRIs.
Research on the value of breast MRI when used in cancer treatment decision is evolving, she says, and not all the answers are in.
The Bleicher study has inherent limitations, she says, because it wasn't a study that randomized people to get one treatment or not. Rather, it was a study that took a look backward, and it lacked some information, such as why some women got MRIs and others didn't.
The findings from the current study, she says, don't hold up at her center.
"This study shouldn't rule out a preoperative MRI,'' she says. "This is one abstract from one center that did one study in a very select group of patients."
She points to another study, published in the Journal of Clinical Oncology, which reviewed the results of 19 studies and found the rate of mastectomy because of false positives on the MRI is 1%.
Breast MRI: Advice for Women
If a woman has suspected or diagnosed breast cancer, Lehman says, she should ask about the potential benefits and risk of a breast MRI.
"Go to a center with a high level of experience," she advises.
Bleicher's advice: "Women who walk into their doctor's office with breast cancer should not be immediately thinking, 'I have to have an MRI.' There are false positives [to MRIs], unnecessary biopsies, a lot of anxiety ... and a three-week delay [to treatment]. All these disadvantages have not been offset by an improvement in our ability to choose the proper treatment."
More study is needed, he says, to decide the best role for breast MRI in cancer diagnosis.
SOURCES: Constance Lehman MD, PHD, professor and vice chair of radiology, head of breast imaging, University of Washington Medical Center, Seattle, and director of imaging, Seattle Cancer Care Alliance. Richard J. Bleicher, MD, surgical oncologist and co-director of the Breast Fellowship Program, Fox Chase Cancer Center, Philadelphia. American Society of Clinical Oncology Breast Cancer Symposium, Washington, D.C., Sept. 5-7, 2008. Houssami, N. Journal of Clinical Oncology, July 1, 2008; vol 26: pp 3248-3258.