Early-stage invasive ductal carcinoma: Association of tumor apparent diffusion coefficient values with axillary lymph node metastasis

PurposeTo evaluate any association between tumor apparent diffusion coefficient (ADC) values and axillary lymph node metastasis (ALNM) in early-stage invasive ductal carcinoma.Materials and methodsRecords of 270 invasive ductal carcinoma patients with stages T1 and T2 disease who underwent breast magnetic resonance imaging, including diffusion-weighted imaging with b values of 0 and 1000s/mm2 were reviewed retrospectively. The tumor ADC values were analyzed for their utility in predicting ALNM using multivariate regression analysis and receiver operating characteristic (ROC) curve analysis.ResultsOf the 270 patients, 58 (21.5%) experienced ALNM. The mean tumor ADC values were significantly lower in patients with ALNM than in those without metastasis (0.880 × 10−3 vs. 0.999 × 10−3 mm2/s, P < 0.001). A ROC curve demonstrated a tumor ADC value of 0.991 × 10−3 mm2/s to be the optimal cut-off for predicting ALNM. In a multivariate analysis, lower tumor ADC (≤0.991 × 10−3 mm2/s; adjusted odds ratio (OR) = 5.861, P < 0.001), large tumor size (>2 cm; adjusted OR = 3.156, P = 0.002) and the presence of lymphovascular invasion (adjusted OR = 4.125, P < 0.001) were independent variables associated with ALNM. When tumor ADC value was added to known risk factors (i.e., tumor size and lymphovascular invasion), a significant improvement in the accuracy of risk prediction for axillary node metastasis was shown (c-statistic = 0.758 vs. 0.816, P = 0.026).ConclusionIn early-stage invasive ductal carcinoma, lower tumor ADC values are associated with the presence of ALNM.