Background A published retrospective data of our study group demonstrated that premenopausal women, patients with lobular invasive breast cancer or patients with high breast density [American College of Radiology (ACR) classification 3+4] significantly benefit from magnetic resonance imaging (MRI) leading to additional detection of malignant foci of 20.2% in the index and 2.5% in the contralateral breast, which would otherwise not be detected by routine imaging. Critics of preoperative MRI focus on higher false-positive rates leading to unnecessary surgical procedures and mastectomies. Therefore, MRI in preoperative imaging remains controversial. Methods To validate our retrospective data we initiate a prospective one-armed multicenter trial for patients with histologically confirmed breast cancer performing routine imaging by ultrasound and mammography followed by MRI imaging based on menopause status, histologic subtype, ACR and Breast Imaging Reporting and Data System (BIRADS)-classification. Primary endpoint is the rate of additional findings and change of treatment strategy, secondary endpoints are local recurrence-free, distant recurrence-free and overall survival. Additional MRI findings are calculated to be above 10% with a number of 100 patients recruited and a power of 80%. Conclusion MRI is detecting more tumor foci than conventional imaging but remains controversial in primary breast cancer for preoperative imaging because of the fear of over-diagnosis and the increased morbidity of additional potentially unnecessary surgical procedures. This planned one-armed prospective multicenter trial is designed to confirm our retrospectively revealed data defining subgroups with significant benefit of preoperative MRI to come to a consensus avoiding over-diagnosis and false-positive results leading to clinically beneficial and cost-effective use of preoperative MRI.
Keywords: MRI; breast cancer; breast imaging; premenopausal; preoperative management; prospective trial.