While MRIs are more expensive, they often detect tumors that mammography does not. The drawback: more false positives.

Karen Wilton learned almost four years ago that she had cancer in her right breast.


Results of a mammogram on her other breast, which was X-rayed as part of an evaluation of her condition, didn’t turn up anything for the Springfield woman to worry about -- or so she thought.


Less than a month later, a more-sophisticated scan that is up to 30 times more expensive than a mammogram, led to the discovery of cancer in her left breast and subsequent surgery to remove both breasts.


“I feel very fortunate that they found it on the other side and took care of it so I could be done with that,” said Wilton, 55.


She received a free MRI, or magnetic resonance imaging scan, as part of a nationwide study published March 29 in The New England Journal of Medicine.


The study’s authors recommended that all women with a breast-cancer diagnosis consider getting an MRI of the opposite breast to check for cancer that may have been missed by mammography, a technology that has helped reduce cancer deaths but isn’t perfect.


An MRI can save lives by detecting breast cancer in the opposite breast when tumors are small and haven’t spread to other parts of the body, according to Dr. Lisa Wichterman, a radiologist who was the lead investigator for the study’s test site in Springfield.


MRIs use a magnet and radio waves to analyze the way a contrast agent injected into the patient is absorbed by the body.


But because of concerns about cost, Wichterman estimated that only 10 percent to 20 percent of newly diagnosed breast-cancer patients receive MRIs.


MRIs cost $2,000 to $3,500, while mammograms cost about $100.


The study’s impact on doctors and the public probably will make MRIs more common among newly diagnosed breast-cancer patients, Wichterman said.


“Patients are pretty knowledgeable anymore about their disease,” she said. “A lot will go to the Internet. A lot of people know what’s out there. So I think more patients will ask their doctors about it.”


The study could make insurers more likely to pay for MRIs, though Wichterman said most insurers will pay for an MRI if a woman already has been diagnosed with cancer.


She said survival from breast cancer probably will increase, and cancer treatment costs will be saved in the long run, through expanded and prudent use of MRIs.


“Anytime we can find a cancer when it’s early, whether it’s breast cancer or colon cancer -- most types of cancer, anyway -- the patient has a better chance of being cured than if the tumor is very large,” she said.


Among the 969 nationwide study participants -- all with recent cancer diagnoses for one breast -- MRIs detected tumors in the other breast in 3 percent, or 30, of the women.


MRIs probably won’t replace mammography as a general breast-cancer screening tool for all women, she said. The test is expensive, she said, noting that U.S. health spending is expected to reach $2.26 billion in 2007, or 16.2 percent of the gross domestic product.


And when done on the general population, MRIs of the breast produce “false-positive” results in up to 20 percent of cases. Those results can lead to unnecessary anxiety for patients and medical complications associated with follow-up MRIs, sonograms and biopsies, Wichterman said.


But the study had a lower “false-positive” rate: 9.4 percent. Ninety-one of the 969 breast-cancer patients who had MRIs of the opposite breast later underwent biopsies that determined they didn’t have cancer.


As a side-benefit, MRIs can help doctors determine the extent of cancer in both breasts and influence the type of treatment that patients receive, Wichterman said.


She recalled a recent case in which an MRI found two more tumors in a woman’s breast after a mammogram turned up only one tumor. That woman had the breast removed rather than a lumpectomy.


Up to 10 percent of women diagnosed with breast cancer in one breast will develop cancer in the other breast, and researchers now believe MRIs -- combined with a clinical breast exam and mammogram -- can find the vast majority of cancers existing in the opposite breast.


Despite the study’s results, federal officials said women who were diagnosed and treated for breast cancer several years ago shouldn’t necessarily get an MRI of their breasts now.


Officials said patients should consult their doctors to talk about risk factors.


Wilton, the Springfield patient, said she felt additional anxiety when an MRI led to a test that showed she had cancer in both breasts, but she was glad the cancer could be removed before it reached any nearby lymph nodes.


Wichterman said that once breast cancer spreads to lymph nodes, “your prognosis for disease-free survival goes way down.”


Springfield State Journal-Register writer Dean Olsen can be reached at dean.olsen@sj-r.com.