Diagnostic efficacy of contrast-enhanced breast MRI versus X-ray mammography in women with different degrees of breast density

Background Detection of breast cancer in women with high breast densities is a clinical challenge. Purpose To study the influence of different degrees of breast density on the sensitivity of contrast-enhanced breast magnetic resonance imaging (CE-BMRI) versus X-ray mammography (XRM). Material and Methods We performed an additional analysis of two large Phase III clinical trials (G1; G2) which included women with histologically proven breast cancers, called "index cancers." Additional cancers were detected during image reading. We compared the sensitivity of CE-BMRI and XRM in women with different breast densities (ACR A -> D; Version 5). For each study, six blinded readers evaluated the images. Results are given as the "Median Reader." Results A total of 774 patients were included, 169 had additional cancers. While sensitivity of CE-BMRI for detecting all index cancers was independent of breast density (ACR A -> D) (G1: 83%-> 83%; G2: 91%-> 91%) the sensitivity of XRM declined (ACR A -> D) (G1: 79%-> 62%; G2: 82%-> 64%). Thus, the sensitivity difference between both imaging modalities in ACR A breasts of 3% (G1) and 9% (G2) increased to 21% (G1) and 26% (G2) in ACR D breasts. Sensitivity of CE-BMRI for detecting at least one additional cancer increased with increasing breast density (ACR A -> D) (G1: 50%-> 73%, G2: 57%-> 81%). XRM's sensitivity decreased (G1: 34%-> 20%) or remained stable (G2: 24%-> 25%). Conclusion CE-BMRI showed significantly higher sensitivity compared to XRM.