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

Abstract

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 × 10(-3) vs. 0.999 × 10(-3)mm(2)/s, P<0.001). A ROC curve demonstrated a tumor ADC value of 0.991 × 10(-3)mm(2)/s to be the optimal cut-off for predicting ALNM. In a multivariate analysis, lower tumor ADC (≤ 0.991 × 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.

Keywords: Diffusion-weighted MRI; Invasive ductal carcinoma; Lymph nodes; Metastasis.