Semiquantitative assessment of wash out parameter in dynamic contrast enhanced MRI for evaluating therapeutic effect of locally advanced breast cancer after neoadjuvant chemotherapy / 中华放射学杂志

ABSTRACT

Objective To study the value of the semiquantitative-parameter analysis of wash out index of time-intensity curve (Swash-out) in evaluating the therapeutic effect of neoadjuvant chemotherapy for locally advanced breast cancer (LABC).Methods Fifty-nine women with LABC underwent dynamic contrast enhancedt MRI examination before chemotherapy,after the 2nd cycle and the 4th cycle of chemotherapy.All patients were divided into major histological response group (MHR) and non-major histological response group (NMHR) according to the final pathologic response.Swash-out and the variancetrends of Swash-out before NAC,after the 2nd cycle of NAC and after the 4th cycle of NAC were compared in each group and between the two groups.According to the gold standard of Miller & Payne criterion,Receiver operating characteristic curve (ROC) analysis was performed to evaluate the predicting effect of Swash-out for NAC response,and to compare it with Semi-quantitative TIC curve indicators Smax (steepest slope) and PPE (peak percent enhancement).Results Fifty-nine patients of LABC patients were divided into a MHR group of 34 patients and a NMHR group of 25 patients.Swash before NAC of MHR group was-16.99 (-56.72-41.20),Swash-out after the 2nd cycle of NAC was 5.66(-69.45-53.08),Swash-out after 4th cycle of NAC was 15.95 (-7.80-54.23).Swash-out before NAC of NMHR group was-23.08 (-64.24-34.39),Swash-out after the 2nd cycle of NAC of NMHR group was-23.01 (-52.72-28.70),Swash-out after 4th cycle of NAC of NMHR group was-11.45 (-50.49-50.93).Swash-out variance rate of MHR group after the 2nd and the 4th cycle of NAC were-1.18 (-31.32-60.86) and 1.50 (-86.27-3.61),respectively.Swash-out variance rate of NMHR group after the 2nd and the 4th cycle of NAC were-0.28(-3.24-9.46) and 0.27 (-5.34-3.11),respectively.Swash-out was not significantly different between the two groups before NAC (Z =-0.97,P ＞0.05).Swash-out and Swash-out variance rate of MHR group after the 2nd cycle of NAC were significant higher than that of NMHR group (Z =-3.97 and-3.02,P ＜0.01).Swash-out and Swash-out variance rate of MHR group after the 4th cycle of NAC were significant higher than that of NMHR group (Z =-3.96 and-3.16,P ＜ 0.01).Area under curve (Az) after the 2nd and the 4th cycle of NAC were 0.805 and 0.804,respectively,and no significant difference was found between them (Z =0.019,P ＞0.05).Diagnostic cut-off points were-8.670 for the 2nd cycle of NAC and 4.105 for the 4th cycle of NAC.Diagnostic sensitivity was 79.42％,specificity was 76.00％ and Youden index was 0.554,for after the 2nd and the 4th cycle of NAC.Conclusion Swash-out of TIC curve before NAC cannot predict the response of NAC,Swash-out of TIC curve after the 2nd cycle of NAC and after the 4th cycle of NAC are efficient in predicting the response of NAC.