MR imaging properties of breast cancer molecular sub-types

Aim: In our study, it was aimed to investigate the magnetic resonance (MR) imaging properties of molecular subtypes, that are an important prognostic marker of breast cancer. Material and method: Preoperative MR examinations of 104 patients, diagnosed with breast cancer according to pathology report, were retrospectively reviewed according to the 5th Edition of Breast Imaging-Reporting and Data System (BI-RADS) atlas. According to BI-RADS, cases were divided into mass or non-mass enhancement. Background parenchymal enhancement of cases were examined. Shape, margin and contrast features of mass enhancements and distribution and internal contrast patterns of non-mass enhancements were examined; finally multifocal/ multicentric (MFMS) status, ADC values, kinetic curves and findings accompanying lesions were examined in all cases. Molecular subtypes and MRI findings were compared by using chi-square and kruskal-wallis tests. Results: The relationship between molecular subtypes and mass/ non-mass enhancement was statistically significant (p=0,017). The subtype with the highest non-mass contrast (enhancement) ratio (%70) was HER-2 (+). It was observed that the shape (p = 0.001) and margin (p = 0.002) features of the masses differed according to molecular subtypes. It was noted that luminal types are mostly irregularly shaped and irregular / spicular margin; HER-2 and Triple (-) subtypes are mostly oval / round shaped and smooth margin. Axillary lymphadenopathy was most commonly (%64.3) observed in Triple (-) subtype (p = 0.033). The subtype with the fastest enhancement ratio (%71.4) was Triple (-). A significant relation was found between early phase kinetic curves and subtypes (p=0,048). Conclusion: In this study, a significant relationship was found between molecular subtypes and many MRI findings, and prospective studies in larger case series will increase our knowledge on this subject. Keywords: BI-RADS, breast cancer, magnetic resonance, molecular subtype, MRI