MRI Breast Cancer Test Benefits High-Risk Women

Magnetic resonance imaging (MRI) may be better than mammography at detecting breast tumors in women who have a family history of or genetic predisposition to breast cancer, according to a report published in The New England Journal of Medicine.

The findings of the new report suggest that MRI be used in addition to mammography for these women. “MRI detected early, potentially curable cancers that in some cases were not picked up by mammography or physical exam,” Dr. Laura Liberman, author of a related editorial, told Reuters Health. However, “MRI was a little less specific than mammography,” meaning it had a higher rate of false-positive results. Despite the greater sensitivity seen with MRI, “I don’t think this study suggests that MRI should be done instead of mammography,” noted Liberman, from Memorial Sloan-Kettering Cancer Center in New York. “In this study, there were some cancers that were seen with mammography, but not with MRI. So, I think the use of MRI we are considering in the high-risk screening setting is as a supplement to mammography.” The findings stem from a study of 1909 women who were screened for breast cancer every six months with physical exam and every year with mammography and MRI. All of the women had a cumulative lifetime breast cancer risk of at least 15% — higher than average — and 358 were carriers of gene mutations that increased their risk of breast cancer. The characteristics of the cancers detected in this group were compared with those of two groups of age-matched controls. The control groups included women who had been diagnosed with breast cancer and who had various risk factor levels. During an average follow-up of three years, 44 invasive cancers, 6 ductal carcinomas in situ, 1 lobular carcinoma in situ, and 1 lymphoma were detected in the study group, senior author Dr. Jan G. M. Klijn, from Erasmus Medical Center in Rotterdam and colleagues report. MRI had a statistically significant better overall discriminating capacity than mammography. The sensitivity for detecting invasive breast cancer ranged from 18 percent for physical exam, 33.3 percent for mammography to 80 percent MRI. The corresponding specificities of the three procedures were 98 percent, 95 percent and 90 percent. About 43 percent of invasive tumors detected in the screening group were no greater than 10 mm in diameter, the authors note. In contrast, only about 13 percent of tumors in the control groups were of this size. Similarly, the proportion of tumors that had spread to the lymph nodes or elsewhere was significantly smaller in the screening group. In high-risk patients, “mammography only picks up about half of their cancers — the other half pops up in the interval between screens,” Liberman explained. “So, it has been suggested that supplementing mammography and clinical exam with some other ancillary test may improve cancer detection. That’s, I think, where MRI comes in.” Liberman said that further studies are needed to determine who will benefit most from MRI screening and how to integrate this test into mammographic screening. (Source: The New England Journal of Medicine: Reuters Health News: Anthony J. Brown, MD: July 2004.)[alink href=”/uploads/VMC/EventFiles/327_EOL_Mammography_study_+_com_May_23.pdf” target=”_blank”]MRI surveillance for hereditary breast-cancer risk[/alink][alink href=”/uploads/VMC/EventFiles/326_UK_press_release.pdf” target=”_blank”]Combined MRI and Mammography More Effective At DetectingBreast Cancer in High-Risk Women[/alink]