Utilization of Magnetic Resonance Imaging in Breast Cancer Screening

Early detection of malignancy through breast cancer screening has contributed significantly to the decline in cancer-related mortality 1 . The U.S. Preventive Services Task Force recently reaffirmed its 2009 stance to begin mammography—the primary screening modality—starting from age 50 and continuing until age 74 2 . However, that recommendation applies primarily to women at “average risk” for developing breast cancer during their lifetime. For women at “high risk,” the American Cancer Society has recommended magnetic resonance imaging (mri) of the breast as an adjunct to annual screening mammography 3 . How, then, is risk defined, and should these guidelines be strictly followed by clinicians? Here, we focus first on describing the quality of mri as a screening tool. Then, we define risk categories and conclude with a discussion of the need for a more nuanced approach to the incorporation of mri into breast cancer screening. In prospective nonrandomized studies across multiple centres throughout the world, contrast-enhanced mri achieves a high sensitivity of 70% –100% in the initial screening (prevalence) setting, compared with 40% or less for mammography in patients at high risk for developing breast cancer 4–6 . The specificity of mri in that setting has been hampered by its difficulty in distinguishing the of ten overlapping features of benign and malignant lesions, causing higher false-positive rates 7 . It is important to note, however, that these oft-cited statistics actually improve significantly in the setting of subsequent (incidence)