Intratumoral heterogeneity of the distribution of kinetic parameters in breast cancer: comparison based on the molecular subtypes of invasive breast cancer

Purpose To evaluate the distribution pattern of kinetic parameters in breast cancers with various molecular subtypes. Materials and methods This study was approved by institutional review board and was compliant with HIPAA. We classified 192 invasive breast cancers of 186 patients into four molecular subtypes using hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) results and evaluated the distribution pattern of kinetic parameters (percent volume of kinetic types relative to the tumor volume) in the molecular subtypes. Results In the delayed phase, all three types of kinetic parameter (persistent, plateau, and washout pattern) were observed in each molecular subtype without any dominant type of kinetic parameter. The percentages of washout pattern in the HR? and HER2-type and triple negative (TN) cancers tended to be lower than those in the other molecular subtype cancers. Conclusion Each molecular subtype of invasive breast cancer showed a heterogeneous kinetic pattern in dynamic-contrast magnetic resonance imaging (MRI). The HR+/HER2-cancers and the TN cancers had relatively lower percentages of washout pattern. When a manual assessment of the kinetic parameters is performed, close attention should be paid in order to identify the malignant washout kinetic pattern, particularly in HR+/HER2-cancer and TN cancer.