Results of MR Imaging Screening for Breast Cancer in High-Risk Patients with Lobular Carcinoma in Situ

Purpose: To determine the outcome of screening breast magnetic resonance (MR) imaging examinations performed in patients with lobular carcinoma in situ (LCIS) at the authors' institution. Materials and Methods: This study was approved by the institutional review board and was compliant with HIPAA. Retrospective review of screening breast MR imaging examinations at the institution from 1996 through September 2009 was performed in patients with prior biopsies demonstrating LCIS. Patients with prior breast cancer diagnosis were excluded. American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) recommendations were recorded. Pathologic results of all consequent biopsies were obtained from the electronic medical records. Results: A total of 445 breast MR examinations in 198 patients with LCIS were identified. Of these, 308 were screening examinations in 134 patients. One patient was a BRCA mutation carrier and was excluded. Of the remaining 307 screening examinations, 254 (82.7%) had BI-RADS category 1 or 2 findings; 27 (8.8%) had BI-RADS category 3 findings; and 27 (8.8%) had B-IRADS category 4 or 5 findings. Of the 27 studies that led to a biopsy recommendation, 10 (37%) yielded benign pathologic findings, five (18.5%) yielded malignant pathologic findings, and seven (25.9%) yielded high-risk lesions. Of the 27 studies with BI-RADS 3 findings, two (7.4%) resulted in biopsy, findings of both were benign. Overall, malignancy was detected in five of 307 screening studies (1.6%) and in five of 133 screened patients (3.8%). The positive predictive value (PPV) of these screening studies for which biopsy was recommended was 18.5%. The PPV 3 (studies for which biopsy was recommended and actually performed, as described in the BI-RADS guidelines) was 23.8%. Conclusion: Screening breast MR imaging helped identify breast cancer in LCIS patients at a rate similar to that shown in high-risk populations for whom screening breast MR imaging is currently consistently recommended. (C) RSNA, 2011