Characterization of tumor and adjacent peritumoral stroma in patients with breast cancer using high-resolution diffusion-weighted imaging: Correlation with pathologic biomarkers

• ADCs of tumor and peritumoral stroma on preoperative HR-DWI are different according to pathologic biomarkers in patients with breast cancer.
• ADC ranges of tumor boundary and adjacent proximal peritumoral stroma are significantly lower in low-risk tumor than in non-low-risk tumors.
• On multivariate analysis, ADC range of proximal PS was the only independent significant parameter to differentiate low-risk tumors from non-low-risk tumors.

PurposeTo assess whether ADC values of tumor and peritumoral stroma (PS) obtained on high-resolution diffusion-weighted imaging (HR DWI) were different according to pathologic biomarkers in patients with breast cancer.MethodsWe retrospectively enrolled 96 patients (age range, 30–75 years; mean, 52 years) with breast cancer who underwent HR DWI at 3T MR scanner. We obtained the apparent diffusion coefficient (ADC) and ADC range of tumor and PS by drawing the region of interest (ROI) of entire tumor. We assessed histopathological features of tumors. ADC values of tumor and PS were compared according to pathologic biomarkers using student t-test and Mann-Whitney U test.ResultsMean ADC of tumor boundary was significantly higher in ER-negative tumors than in ER-positive tumors (P = 0.005). The ADC ranges of tumor boundary and proximal PS were significantly higher in tumors with high nuclear grade, negative ER, positive HER2, positive Ki67, and lymph node metastasis than those with low nuclear grade, positive ER, negative HER2, negative Ki67, and without lymph node metastasis (P < 0.05 for all). ADC range of tumor boundary and proximal PS was significantly lower in low risk tumor than in the others (P = 0.004 and 0.002). Mean ADC of whole tumor was significantly higher in low-risk tumor than in non-low-risk tumor (P = 0.030).ConclusionOn HR DWI, ADC ranges of tumor boundary and adjacent proximal PS were significantly lower in low-risk tumor than in non-low-risk tumors.