The fight against breast cancer appears to have a new tool: magnetic resonance imaging (MRI) scans. On March 27, the American Cancer Society issued new guidelines that recommend MRIs in conjunction with yearly mammograms for certain women.
But who should get these tests, and do the costs -- both financially and emotionally -- outweigh the benefits?
Known largely for their use in imaging active areas of a person's brain, MRI scans generally measure tissue density. Because cancerous regions differ in density from normal tissue, MRI scans can also be used to detect cancers in tissue other than brains.
An advisory board of the American Cancer Society analyzed studies that looked at whether MRIs can pick out tumors in women's breasts and decided that for a small group of women at high risk for getting breast cancer, MRIs can be quite helpful in finding small tumors. A study published the same week in the New England Journal of Medicine reported that MRIs found undetected cancers in the other breast of 3% of women who were newly diagnosed with breast cancer.
Even before release of these findings and the American Cancer Society's recommendations, discussion of MRI usage in breast cancer screening had created confusion and concern, experts say. Adding to the muddle, last week the American College of Physicians released a statement challenging the need for routine mammograms for women younger than 50, and a new study questioned the effectiveness of computerized mammography, a higher-tech mammogram, in detecting tumors.
If MRI scans are better than mammograms at detecting tumors in women, isn't the MRI a superior test, and shouldn't \o7all \f7women get one, not just women at elevated risk? "I've even been getting e-mails from doctors wondering about this," says Dr. Joann Elmore, an internist at the University of Washington School of Medicine in Seattle.
But Elmore says the recommendations are clear: "The great majority of women in the United States should not be getting MRI scans for breast cancer screening."
The test, cancer experts say, is very expensive -- about 10 times the cost of a mammogram. Women who aren't high risk would probably have to pay for it out of pocket, they add. And in any case, its benefit for women with low cancer risk is unknown. "The value of MRIs has not been studied in the average population," Elmore says.
