The benefits of breast MRI

Connie Lehman's study, American Cancer Society guidelines support addition of MRI to mammography for cancer detection in opposite breasts
Dr. Connie Lehman
Dr. Connie Lehman led a study that found adding magnetic-resonance imaging scans to examinations of women with breast cancer vastly improves detection of a second cancer in the opposite breast. New recommendations from the American Cancer Society back Lehman's results. University of Washington Photo

Heidi Trott is convinced that the magnetic resonance-imaging scan she asked for last year at the Seattle Cancer Care Alliance saved her life. The three-time breast-cancer survivor, who is 46 years old, wanted the scan of her left breast when her original cancer recurred in her right breast. A nurse practitioner, Trott knew that magnetic resonance imaging, or MRI, is more sensitive than mammography in detecting tissue abnormalities, particularly in women like herself, who have dense breast tissue.

The MRI did find cancer in her opposite, or contralateral, breast. It was surprising news to Trott, who had asked for the scan for "peace of mind." However, due to her diligence, the new cancer was detected at an earlier stage than her previous disease and was less aggressive. Today, disease-free, she volunteers with an organization that provides emotional support for women who are newly diagnosed with breast cancer. "I often recommend that women ask their provider about breast MRI," she said.

Although Trott's experience and awareness of MRI are not the norm, her case bears out what SCCA-affiliated researchers published in late March: MRI scans of women who were diagnosed with cancer in one breast detected more than 90 percent of cancers in the other breast that were missed by mammography and clinical breast exam at initial diagnosis. The study, led by Dr. Connie Lehman, director of radiology at the SCCA, was published in the New England Journal of Medicine the same day that the American Cancer Society (ACS) issued new guidelines for when certain women who are at risk of getting breast cancer should add an MRI scan to their annual mammogram.

The dual announcements, coupled with the revelation less than a week earlier that breast cancer had recurred and metastasized in Elizabeth Edwards, wife of presidential hopeful John Edwards, created an intense media spotlight on the disease and how best to detect it. The study and guidelines helped solidify the role of MRI in addition to mammography in certain diagnostic situations.

The ACRIN trial

"We can now identify the vast majority of contralateral cancers at the time of a woman's initial breast-cancer diagnosis," said Lehman, who was principal investigator of the American College of Radiology Imaging Network (ACRIN) Breast MRI Trial, and is a professor of radiology and director of breast imaging at the University of Washington and the SCCA. "This means that instead of those women having another cancer diagnosis years after their initial treatment, we can diagnose and treat those opposite breast cancers at the time of the initial diagnosis."

Researchers hope that with breast MRI's strong ability to predict the absence of a tumor, they can avoid some unnecessary mastectomies and provide women with more reassurance that the opposite breast is disease free. "Although no imaging tool is perfect, if the MRI is negative, the chance of cancer in that breast is extremely low. A potential outcome that we would be delighted to see is fewer unnecessary bilateral mastectomies," Lehman said.

The ACRIN trial was designed to determine whether the use of MRI could improve upon clinical breast exam and mammography in detecting breast cancer in the opposite breast at the time of the initial breast-cancer diagnosis. The study recruited 1,007 women from 25 institutions who had a recent diagnosis of cancer in one breast. Of these, 969 women completed the study, which began in April 2003. All of the women enrolled had a negative mammogram and negative clinical breast exam of the opposite breast within 90 days prior to the MRI. After receiving an MRI, 33 contralateral breast cancers were diagnosed in the study. Thirty of these tumors, or 91 percent, were diagnosed as a result of MRI. The other three cancers were detected due to subsequent mastectomies. Researchers found that the added benefit of MRI was consistent, regardless of a woman's cancer type, age or breast density. Dense breasts have more glandular and connective tissue as well as less fat tissue.

For most women, the fear of a second cancer diagnosis is quite high. The researchers hope that breast MRI can improve a woman's quality of life both at the time of her diagnosis and the years following. Researchers are optimistic that there may be long-term savings to patients and to the health-care system due to MRI's ability to detect cancer in both breasts prior to therapy — which may result in fewer rounds of chemotherapy and breast surgeries.

Lehman is a member of the ACS Breast Cancer Advisory Group and co-author of the new guideline for adding an MRI scan to an annual mammogram for women considered to be at high risk for breast cancer.

Lehman co-authors new American Cancer society guidelines for MRI screening

Most high-risk women should begin getting MRIs and mammograms at age 30, the new guidelines say, unless they and their doctor think it's better to begin at a different age. Published in a recent issue of the ACS journal CA: A Cancer Journal for Clinicians, the guideline recommends MRI screening in addition to mammograms for women who meet at least one of the following conditions:

  • They have a BRCA1 or BRCA2 mutation;
  • they have a first-degree relative (parent, sibling, child) with a BRCA1 or BRCA2 mutation, even if they have yet to be tested themselves;
  • their lifetime risk of breast cancer has been scored at 20 percent to 25 percent or greater, based on one of several accepted risk assessment tools that look at family history and other factors;
  • they had radiation to the chest between the ages of 10 and 30; or
  • they or a first-degree relative have Li-Fraumeni, Cowden or Bannayan-Riley-Ruvalcaba syndromes.

The recommendations are based on studies that were published after the ACS last revised its breast cancer early detection guidelines in 2002-2003. At that time, the panel concluded there was not enough evidence to recommend for or against the use of MRI in high-risk women, so the guideline advised these women to make the decision after talking with their doctor. Now there is more solid evidence that MRI is useful for certain women.

"These guidelines address the importance of MRI in the early detection of breast cancer among women at high risk," Lehman said. "As with other solid tumors, the sooner breast cancer is detected, the easier it is treated, and the more likely it is to be cured."

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