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MRI Outdoes Mammography in Diagnosing DCIS


 

CHICAGO — Magnetic resonance imaging offers significantly higher sensitivity for diagnosing pure ductal carcinoma in situ than does mammography, Dr. Christiane Kuhl said at the annual meeting of the Radiological Society of North America.

She presented data from a prospective study of 137 women in which almost half of all ductal carcinomas in situ (DCIS) and more than half of high-grade DCIS tumors were missed by mammography. The majority of the women studied were not considered at high risk for cancer, said Dr. Kuhl of the University of Bonn, Germany.

“If proper diagnostic criteria are being used, MRI allows the diagnosis of DCIS that goes undetected by mammography and also ultrasound,” she said.

The women were part of a larger study in which 5,612 consecutive patients underwent screening and diagnostic mammography with at least two views, plus spot compression views if necessary, and contrast-enhanced bilateral high-resolution MRI. Of these, 137 were diagnosed with pure noninvasive intraductal cancer. Their mean age was 55 years (range 20–75).

Both mammography and MRI resulted in positive findings for about 50% of all cases; 2% of cases were undetected by both modalities; 8% of cases had positive findings only with mammography; and 40% had positive findings only with MRI. Overall sensitivity for MRI was 90%, compared with 58% for mammography, Dr. Kuhl and colleagues reported.

Sensitivity for low-nuclear-grade tumors (grades 1–2) was 78% for MRI and 71% for mammography. For high-grade tumors, MRI detected 98% of cases, compared with just 49% for mammography.

Sensitivity for ER/PR-negative and HER 2-positive tumors was 100% and 91%, respectively, for MRI compared with 50% and 48% for mammography.

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