Added Value of Breast MRI for Preoperative Diagnosis of Ductal Carcinoma In Situ: Diagnostic Performance on 362 Patients.

INTRODUCTION: The purpose of this study was to evaluate the added value of breast magnetic resonance imaging (MRI) in preoperative diagnosis of ductal carcinoma in situ (DCIS). We reviewed our institution database of 3499 consecutive patients treated for breast cancer. PATIENTS AND METHODS: A total of 362 patients with histologically proven DCIS were selected from the institutional database. Of these, 245 (67.7%) preoperatively underwent conventional imaging (CI) (mammography/ultrasonography) (CI group), and 117 (32.3%) underwent CI and dynamic MRI (CI + MRI group). The pathology of surgical specimens served as a reference standard. The Mann-Whitney U, χ2 test, and Spearman correlation coefficient were performed. RESULTS: The CI + MRI group showed a sensitivity of 98.5% with an increase of 10.1% compared with the CI group to detect pure DCIS. Dynamic MRI identified 19.7% (n = 13) additional pure DCIS compared with CI. In the CI + MRI group, a single (1.5%) false negative was reported, whereas in the CI group, 11 (11.6%) false negatives were reported. Moreover, the CI + MRI group showed a sensitivity of 98.0% to detect DCIS + small invasive component. In this group, dynamic MRI identified 21.6% (n = 11) additional DCIS and a single (2.0%) false negative compared with the CI group, whereas in the CI group, 7 (4.7%) false negatives were reported. MRI and histopathologically measured lesion sizes, Breast Imaging Reporting and Data System MRI assessment categories, and enhancement signal intensity curve types showed a significant correlation. The MRI detection rate of DCIS increased significantly with increasing nuclear grade. CONCLUSIONS: Preoperative breast MRI showed a better accuracy then CI in preoperative diagnosis for both pure DCIS and DCIS + small invasive component with a precise assessment of lesion size. This can provide a more appropriate management of DCIS patients.