Utilization of Magnetic Resonance Imaging in Breast Cancer Screening

Abstract

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][5][6] . The specificity of mri in that setting has been hampered by its difficulty in distinguishing the often 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) screening rounds. As noted by Warner et al. 6 , the rate of benign biopsy is reduced by nearly one half from the initial screening round to the second screening round (11% vs. 6.6%). In a study of mri screening in BRCA mutation carriers and women with high familial risk, Riedl et al. 8 highlighted the improvement in mri specificity from the first screening round to subsequent screening rounds. In addition, mri recall rates in their study declined dramatically from 26% on initial screening to 13% on second screening and 10% on third screening, emphasizing an improvement with successive rounds of screening. That finding was reinforced by Chiarelli and colleagues 9 in their report of the Ontario Breast Screening Program evaluating mri and mammography in high-risk women. Those authors observed lower recall rates with subsequent rounds of screening (when images from a baseline mri are available for comparison) and with increased experience of mri use at testing centres. As noted by Chiarelli et al., mri screening might be criticized for achieving lower positive predictive values, but two thirds of the cancers would be otherwise missed. Therefore, acceptance of a lower positive predictive value of mri screening in return for the gain of a higher detection rate must be considered. In addition, mri can offer an important contribution to the detection of ductal carcinoma in situ (dcis). Kuhl et al. 10 note that more than half of dcis lesions detected only by mri are histologic...

The Mammography Debate, Round Two: Science, Smoke and Mirrors

“…The important and closely-reasoned paper ("Utilization of magnetic resonance imaging in breast cancer screening" 14 ), from a team of New York University oncology experts serves as an invaluable reminder that different evidence-based recommendations are needed to assess the precise role and value of screening mri for early breast cancer detection in elevated-risk populations, and that little in the way of "received wisdom" can be taken for granted here. If you thought you knew what is important to know about screening mri, think again; this paper is the corrective.…”

The Mammography Debate: The Senior Years

“…Research Institute) will explore the benefits of fast breast mri 7 as a screening technique in women with a personal history of cancer (fast mri plus annual mammography vs. annual mammography alone). And in connection, the Ultra FAST Breast Magnetic Resonance in Breast Cancer Screening trial (Brugmann University Hospital, Belgium) will explore the benefits of the ultra-fast streamlined mri protocol 7,20 in normal screening populations.…”