Several authors question the potential benefit of preoperative magnetic resonance imaging (MRI) against the background of possible overdiagnosis, false-positive findings, and unnecessary resections in patients with newly diagnosed breast cancer. In order to reveal a better selection of patients who should undergo preoperative MRI after histological confirmed breast cancer, the present analysis was implemented. We aimed to evaluate the influence of preoperative breast MRI in patients with newly diagnosed breast cancer to find subgroups of patients that are most likely to benefit from preoperative MRI by the detection of occult malignant foci. A total of 1102 consecutive patients who underwent treatment for primary breast cancer between 2002 and 2013 were retrospectively analyzed. All patients underwent triple assessment by breast ultrasound, mammography, and bilateral breast MRI. MRI findings not seen on conventional imaging that suggested additional malignant disease was found in 344 cases (31.2 %). Histological confirmed malignant foci were found in 223 patients (20.2 %) within the index breast and in 28 patients (2.5 %) in the contralateral breast. The rate of false-negative biopsies was 31 (2.8 %) and 62 (5.6 %), respectively. Premenopausal women (p = 0.024), lobular invasive breast cancer (p = 0.02) as well as patients with high breast density [American College of Radiology (ACR) 3 + 4; p = 0.01] were significantly associated with additional malignant foci in the index breast. Multivariate analysis confirmed lobular histology (p = 0.041) as well as the co-factors "premenopausal stage" and "high breast density (ACR 3+4)" (p = 0.044) to be independently significant. Previous studies revealed that breast MRI is a reliable tool for predicting tumor extension as well as for the detection of additional ipsilateral and contralateral tumor foci in histological confirmed breast cancer. In the present study, we demonstrate that especially premenopausal patients with high breast density as well as patients with lobular histology seem to profit from preoperative MRI.

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