Magnetic resonance imaging and mammography in women with a hereditary riskof breast cancer

Background: Although breast cancer screening is recommended to start at a y ounger age for women with a hereditary risk of breast cancer, the sensitivi ty of mammography for these women is reduced. We compared magnetic resonanc e imaging (MRI) with mammography to determine which is more sensitive and w hether MRI could play a role in the early detection of breast cancer for th ese women, Methods: We constructed a retrospective cohort of all breast MRI and mammog raphy surveillance reports made in our department from November 1994 to Feb ruary 2001, All of the 179 women in the cohort had received biannual palpat ion in addition to annual imaging by MRI, mammography, or both. The 258 MRI images and the 262 mammograms were classified with the use of the BI-RADS (TM) (i.e., Breast Imaging Reporting and Data System) scoring system, which has five categories to indicate the level of suspicion of a lesion. Receiv er operator characteristic curves were generated for MRI and mammography, a nd the area under each curve (AUC) was assessed for the entire cohort of 17 9 women and for a subset of 75 women who had received both an MRI and a mam mographic examination within a 4-month period. All statistical tests were t wo-sided. Results: In the cohort of 179 women, we detected 13 breast cancers. Seven c ancers were not revealed by mammography, but all were detected by MRI, For the entire cohort, the AUC for mammography was 0.74 (95% confidence interva l [CI] = 0.68 to 0.79), and the AUC for MRI was 0.99 (95% CI = 0.98 to 1.0) , For the subset of women who had both examinations, the AUC for mammograph y was 0.70 (95% CI = 0.60 to 0.80), and the AUC for MRI was 0.98 (95% CI = 0.95 to 1.0), Conclusion: R IRI was more accurate than mammography in annual breast cance r surveillance of women with a hereditary risk of breast cancer. Larger pro spective studies to examine the role of MRI in screening programs are justi fied.