MRI characteristics of BRCA-associated breast cancers.

Abstract

1596 Background: Magnetic resonance imaging (MRI) is the preferred imaging modality for screening and diagnosis of breast cancer in BRCA-1and BRCA-2 mutation carriers. However, there is limited data on the radiographic features of BRCA1/2-positive breast cancers on MRI. This study evaluates the MRI characteristics of BRCA1/2 -related breast cancers. Methods: All female BRCA mutation carriers with a biopsy proven breast cancer, imaged with MRI for screening or preoperative evaluation at William Beaumont hospital between April 2002 until January 2011, were included in the study. A total of 47 mutation carriers were identified.All MRI examinations were retrospectively evaluated by an independent radiologist for the following characteristics: shape, margin, enhancement, T2 intratumoral intensity. Results: A majority of BRCA- associated breast tumors were morphologically irregular, hypodense lesions on MRI with heterogeneous enhancement. No statistically significant differences were noted among the BRCA-1 and -2 mutations carriers. Conclusions: Previous studies have reported that BRCA-associated breast cancers demonstrate morphological characteristics that resemble benign tumors i.e.round shape and smooth margins. Our study however, showed features more typical of malignant lesions i.e. irregular shape and margin. Low T2 intratumoral intensity tumors were commonly seen in our cohort, although BRCA1 patients often develop triple negative tumors which typically are high intensity. These differences may be explained by small sample size or population differences. Future reasearch is needed with larger patient cohorts to elucidate the unique MRI characteristics of BRCA- related cancers. MRI Characteristic BRCA1 BRCA2 BRCA1+2 Shape Round 3 4 7 (14.3%) Lobulated 8 3 11 (22.4%) Irregular 19 12 31 (63.3%) Margin Smooth 3 3 6 (12.2%) Irregular 26 17 43 (87.8%) Enhancement Homogenous 5 2 7 (14.3%) Heterogenous 19 13 32 (65.3%) Rim 5 5 10 (20.4%) T2 intratumoral intensity Low 25 21 46 (86.8%) Equal 4 0 4 (7.6%) High 1 2 3 (5.7%)