Role of Breast MRI in the Preoperative Evaluation of Patients with Newly Diagnosed Breast Cancer

OBJECTIVE. The purpose of our study was to evaluate in a noninvestigational setting the effect of preoperative breast MRI on the diagnosis of unsuspected additional malignant tumors and on surgical management choices. SUBJECTS AND METHODS. One hundred ninety-nine patients with a new diagnosis of breast cancer who underwent preoperative bilateral breast MRI were enrolled. Data included additional imaging and biopsies performed, final surgical management, and pathologic correlation. To reduce bias due to patient preference and variable surgical approaches, ipsilateral malignant lesions found on breast MR images were retrospectively reviewed by a surgeon blinded to final surgical treatment. RESULTS. MRI detected additional suspicious previously unsuspected lesions in 74 patients (37%). Fifty-four of these lesions, in 38 patients (19%), were identified as malignant, of which 41 (76%) were invasive. Retrospective review of the MRI-identified ipsilateral malignant lesions resulted in hypothetical recommendations that would have altered the surgical treatment of 26 of the patients (13%), principally as mastectomy or wider excision. CONCLUSION. For patients with a new diagnosis of breast cancer, breast MRI in a mid-sized regional hospital depicts unsuspected malignant lesions in both the ipsilateral and contralateral breasts in proportions consistent with the results of earlier studies at larger institutions. Whether clinical outcome is improved by changes in surgical management consequent to MRI detection of unsuspected malignant lesions remains unproven.