Impact of Pre-Operative Breast Magnetic Resonance Imaging (MRI) on Contralateral Synchronous and Metachronous Breast Cancer Detection- A Case Control Comparison Study With Mean Follow-Up of 102 Months.
Abstract Background: Women with unilateral breast cancer are at an increased risk for the development of contralateral breast cancers. We hypothesis that combined breast MRI would detect more contralateral synchronous breast cancer than conventional imaging alone, and resulted in less contralateral metachronous breast cancer during follow-up. Methods: In this case control analysis, we retrospectively collected two groups of patients for evaluating the effectiveness and value of adding pre-operative breast MRI to conventional breast images (mammography and sonography) for detection of contralateral synchronous breast cancer. The new metachronous contralateral breast cancer diagnosed during follow-up was prospectively evaluated and compared. Results: Group A (n=733) comprised patients who underwent conventional preoperative imaging and group B (n=735) combined with MRI were enrolled and compared. Seventy (9.5%) of the group B patients were found to have contralateral lesions detected by breast MRI, and 65.7% of these lesions only visible with MRI. The positive predictive value of breast MRI detected contralateral lesions was 48.8%. With the addition of breast MRI to conventional imaging studies, more surgical excisions were performed in contralateral breasts (6% (44/735) versus 1.4% (10/733), P< 0.01), more synchronous contralateral breast cancer detected (2.9% (21/735) versus 1.1% (8/733), P=0.02), and resulted in numerical less (2.2% (16/714) versus 3% (22/725), p=0.3) metachronous contralateral breast cancer during a mean follow-up of 102 months. Conclusions: Combining pre-operative breast MRI evaluation resulted in an increase of contralateral synchronous breast cancer detection, and a numerical less subsequent contralateral metachronous breast cancer occurrence compared to conventional imaging alone.