Screening Breast MRI in Patients Previously Treated for Breast Cancer: Diagnostic Yield for Cancer and Abnormal Interpretation Rate

Rationale and Objectives: To determine the cancer detection rate and abnormal interpretation rate of screening breast magnetic resonance imaging (MRI) in previously treated breast cancer patients. Materials and Methods: Institutional review board-approved retrospective review of the breast MRI database from 2009 to 2011 identified a total of 3297 screening examinations. After excluding genetic mutation carriers, untested first-degree relatives of known mutation carriers, and patients with a history of chest irradiation, there were 1194 (36.2%) examinations in 691 patients previously treated for breast cancer. MRI reports were reviewed to determine MRI findings and breast imaging reporting and data system (BI-RADS) assessments. The longitudinal medical record was reviewed to determine patient demographics and outcomes of imaging surveillance and biopsy. Results: Mean patient age at initial cancer diagnosis was 46.1 years, and mean patient age during the study interval was 52 years. Cancer detection rate was 10 per 1000 (1%; 95% confidence interval [CI], 0.5%-1.8%]; 12 of 1194 examinations). Overall 10.7% (128 of 1194) of examinations received an abnormal interpretation, including 5.4% (65 of 1194) BI-RADS 4 or 5 and 5.3% (63 of 1194) BI-RADS 3 assessments with a 9.4% positive predictive value (PPV1; 12 of 128 examinations) and a 17.9% PPV3 (12 malignancies per 67 biopsies). Conclusions: Screening breast MRI in women previously treated for breast cancer detected cancer in 1.0% of examinations, with a 10.7% abnormal interpretation rate, and a PPV for malignancy of 17.9%.