NEW YORK (Reuters Health) – MRI of the breast has the greatest potential, compared with digital mammography or whole-breast ultrasound, for detecting cancers missed by film screen mammogram, study findings indicate.

There are few well-controlled studies comparing all three modalities, Dr. Susan P. Weinstein and co-authors assert in their report in the Journal of Clinical Oncology for November 2.

The researchers, all from the University of Pennsylvania Health System in Philadelphia, conducted a prospective study comparing digital full-field mammography, ultrasound, and contrast-enhanced MRI in high-risk women with nonactionable film screen mammography and negative clinical screens. Imaging was bilateral except when breast cancer had recently been diagnosed in a contralateral breast.

Risk factors were mutations in BRCA1 or BRCA2 genes, >25% lifetime risk based on Claus or Gail models, history of chest wall radiation before puberty, previous diagnosis of lobular carcinoma in situ or atypical hyperplasia, or a recent breast cancer diagnosis.

The study cohort included 609 women ages 27 to 81 who underwent consecutive imaging on the same day. In total, 11 invasive cancers were detected in 11 patients and 9 ductal carcinomas in situ were detected in 7 patients.

Sensitivity was highest for MRI at 0.71, with a specificity of 0.79. Corresponding sensitivity and specificity were 0.33 and 0.94 for film screen mammography; 0.39 and 0.91 for digital mammography; and 0.17 and 0.88 for ultrasound.

The cancer yield by modality was 2.1% for MRI, 1.2% for digital mammography, 1.0% for film screen mammography, and 0.53% for ultrasound.

Dr. Weinstein