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

Purpose: To evaluate any association between tumor apparent diffusion coefficient (ADC) values and axillary lymph node metastasis (ALNM) in early-stage invasive ductal carcinoma. Materials and methods: Records 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/mm(2) 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. Results: Of 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 x 10(-3) vs. 0.999 x 10(-3) mm(2)/s, P< 0.001). A ROC curve demonstrated a tumor ADC value of 0.991 x 10(-3) mm(2)Is to be the optimal cut-off for predicting ALNM. In a multivariate analysis, lower tumor ADC (<0.991 x 10(-3) mm(2)/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). Conclusion: In early-stage invasive ductal carcinoma, lower tumor ADC values are associated with the presence of ALNM. (C) 2015 Elsevier Ireland Ltd. All rights reserved.