Quantitative dynamic contrast enhanced MR in the prediction of response in breast cancer patients undergoing neoadjuvant chemotherapy

Objective: To investigate whether quantitative dynamic contrast enhanced MR can predict final pathologic response in primary breast cancer patients undergoing neoadjuvant chemotherapy (NAC). Methods: Forty seven patients who were pathologically proved infiltrating ductal carcinoma with core needle puncture biopsy were examined before NAC and after 2 cycles of treatment and the quantitative parameters (K^trans, K_ep and V_e) were analyzed prospectively. Histological response is categorized as non-major histological response (NMHR) and major histological response (MHR). Quantitative parameter changes measured after 2 cycles of NAC were compared between MHR and NMHR using non parametric tests (Mann-Whitney U test) and pretreatment parameters were compared using independent samples t tests. Receiver operating characteristic curve (ROC) was used to determine the best predictor and cutoff value. Results: Fifteen patients were grouped into MHR and 32 patients were NMHR. Pretreatment parameters (K^trans, K_ep and V_e) were (1.51 ± 0.33)/min, (2.97 ± 1.06)/min and (0.55 ± 0.16) in MHR and (1.53 ± 0.40)/min, (2.82 ± 0.99)/min and (0.57 ± 0.20) in NMHR. There was no significant difference between the two groups (t values were -0.123, 0.450 and -0.380, respectively, P > 0.05). Changes in kinetic parameters(K^trans, and V_e) were -88.2% (-96.0% to 1.5%), -62.5% (-94.3% to -8.7%) and -57.0%(-82.1% to 55.5%) in MHR and -8.1% (-88.5% to 32.4%), -18.2% (-62.1% to 145.9%) and -4.7% (-83.1% to 95.7%) in NMHR. There were significant difference between the two groups (Z values were 4.359, 4.359 and 3.332, respectively, P < 0.01). The areas under ROC curve of ΔK^trans, ΔK_ep and K^trans after 2 cycles of NAG were all 0.898. Sensitivity of the three parameters for predicting NMHR were 87.5%, 90.6% and 78.1%, and specificity were 86.7%, 80.0% and 93.3%, respectively. Conclusion: Quantitative dynamic contrast enhanced MRI can predict final pathologic response in primary breast cancers after 2 cycles of NAC. (authors)