RESUMEN
AIMS: The role of magnetic resonance imaging (MRI) in the local staging of breast cancer is currently uncertain. The purpose of this prospective study is to evaluate the accuracy of preoperative MRI compared to conventional imaging in detecting breast cancer and the effect of preoperative MRI on the surgical treatment in a subgroup of women with dense breasts, young age, invasive lobular cancer (ILC) or multiple lesions. METHODS: Between January 2006 and October 2007, 91 patients with newly diagnosed breast cancer underwent preoperative clinical breast examination, mammography, bilateral breast ultrasonography and high-resolution breast MRI. All patients had histologically verified breast cancer. The imaging techniques were compared using the final pathological report as gold standard. RESULTS: The sensitivity of MRI for the main lesion was 98.9%, while for multiple lesions sensitivity was 90.7% and specificity 85.4%. After preoperative MRI, 13 patients (14.3%) underwent additional fine needle/core biopsies, 9 of whom had specimen positive for cancer. Preoperative MRI changed the surgical plan in 26 patients: in 19.8% of the cases breast conservative surgery was converted to mastectomy and in 7.7% of the patients a wider excision was performed. At a mean follow-up of 48 months, 2 local recurrences occurred (local failure rate = 2.5%). CONCLUSIONS: Enhanced sensitivity of breast MRI may change the surgical approach, by increasing mastectomy rate or suggesting the need of wider local excision. MRI can play an important role in preoperative planning if used in selected patients with high risk of multifocal/multicentric lesions. However, the histologic confirmation of all suspicious findings detected by MRI is mandatory prior to definite surgery.