Additional lesions seen in magnetic resonance imaging of breast cancer patients: the role of second-look ultrasound and imaging-guided interventions

Purpose The purpose of this study was to investigate the final outcomes of magnetic resonance imaging (MRI)-identified additional lesions (MRALs) in breast cancer patients and the role of second-look ultrasound (SLUS) and imaging-guided interventions. Methods We analyzed breast cancer patients with MRALs on preoperative MRI between January and June 2012. MRALs were defined as additional lesions suspected on MRI but not suspected on mammograms or ultrasound. The malignancy rate of MRALs, MRI-based Breast Imaging Reporting and Database System (BI-RADS) category, positional relationship with the index cancer, MRI-concordant lesion visibility on SLUS, performance of imaging-guided interventions, and total mastectomy (TM) rates were evaluated for the confirmed lesions. Results Among the 119 confirmed lesions, SLUS and imaging-guided interventions were performed in 94 (79.0%) and 82 cases (68.9%), respectively. The malignancy rate was 68.1% (81 of 119), and was significantly higher in BI-RADS 4C-5 lesions than in 4A-4B lesions (94.6% vs. 56.1%, P<0.01) and in ipsilateral same-quadrant lesions than in contralateral lesions (84.2% vs. 33.3%, P