Evaluation And Early Prediction Of The Efficacy Of Neoadjuvant Chemotherapy For Locally Advanced Breast Cancer By Quantitative Parameters Of DCE-MRI

Objectives: To investigate the value of dynamic contrast-enhanced magnetic resonance quantitative parameters in the evaluation and early prediction of neoadjuvant chemotherapy efficiency for locally advanced breast cancer.Materials and Methods: A total of 55 patients with locally advanced breast cancer(clinical stage II/III)who underwent pathological biopsy confirmed invasive ductal carcinoma between June 2014 and March 2018 and who underwent neoadjuvant chemotherapy before surgery were enrolled.All patients underwent Dynamic contrast-enhanced magnetic resonance imaging before,after 2 and 4 cycles of NAC and the maximum diameter of the tumor three azimuths and the quantitative parameter including capacity transfer constant Ktrans,rate constant Kep,and plasma fraction Vp were measured.According to the RECIST criteria,a tumor with a maximum diameter reduction of 30% or more was regarded as a significant effective group,less than 30%,or a lesion enlargement was regarded as a non-significant effective group.The independent sample t test was used to compare the changes of Ktrans,Kep and Vp before NAC between the significant effective group and the non-significant effective group.The change of Ktrans,Kep and Vp values before,after 2 and 4 cycles of NAC was compared with the significant effective group and the non-significant effective group by paired sample t-test.Non-parametric tests were used to compare the parameter changes after the early(2 cycles)of the neoadjuvant therapy in the significantly effective group and the non-significant effective group.The receiver operating characteristic curve(ROC)was drawn,the area under the curve,specificity and sensitivity were calculated,and the optimal parameters and diagnostic thresholds for predicting the efficacy of NAC in advanced breast cancer were found.Results:1.Comparison of DCE-MRI quantitative parameter values between significant and non-significant effective groups before NAC treatment There were 38 patients in the significant effective group and 17 patients in the non-significant effective group.The Ktrans,Kep and Vp values of the significant effective group before NAC treatment were 1.319±0.451min-1,1.591±0.369min-1 and0.415±0.287,respectively,and the non-significant effective group was1.225±0.353min-1,1.616±0.619 min-1and 0.568±0.560,respectively,there was no statistical difference between the two groups(P>0.05);2.Comparison of DCE-MRI quantitative parameter values between significant and non-significant effective groups before and after NAC treatment In the significant effective group,the Ktrans values after NAC2 cycle and after 4cycles were 0.977±0.361min-1,0.721±0.505min-1,respectively.the Kep values after the NAC2 cycle and after 4 cycles were 1.028±0.293min-1 and 0.823±0.361min-1,respectively,which were significantly lower than those before NAC,the differences were statistically significant(P<0.05);Vp values were 0.353±0.266 and 0.369±0.356 after NAC2 and 4,respectively,which was lower than before NAC,but the difference was not statistically significant(P>0.05);In non-significant effective group,the Ktrans values after NAC2 cycle and after 4 cycles were 1.281±0.434min-1 and0.989±0.563min-1,respectively.After the NAC2 cycle,Ktrans increased than that before NAC and decreased slightly than that after NAC4 cycle,the difference was not statistically significant(P>0.05,).After the NAC2 cycle and 4 cycles,the Kep values were 1.556±0.377min-1 and 1.383±0.454min-1,the Vp values were 0.315±0.215 and0.268±0.261,respectively,which were slightly lower than those before NAC,but the difference was not statistically significant(P>0.05).3.Comparison of changes of parameter between significant and non-significant effective groups after early NAC(2 cycles)treatment In the significant effective group,?Ktrans and ?Kep were-17.524(-37.252~-3.200)and-41.613(-50.105~-13.875)after NAC 2 cycle,respectively;in non-significant effective group,?Ktrans and ?Kep were 0.654(-13.980~35.343)and-4.823(-37.521~35.920)after NAC 2 cycles,the difference for ?Ktrans and ?Kep was statistically significant.The Z values were-2.659 and-3.060,respectively,and the P values were 0.014 and 0.002,respectively.The ?Vp of the significantly effective group and the non-significant effective group were-19.035(-67.004-5.913)and-34.043(-56.516-57.187)after the NAC2 cycle,and the Z value was-0.073,and the P value was0.942.4.The selection of the best parameters of DCE-MRI ROC curve analysis showed that the area under the curve,the diagnostic threshold,sensitivity and specificity were 0.709,-0.20,50.00 and 88.24,respectively,of ?Ktrans predicting neoadjuvant chemotherapy efficiency after NAC2 cycle;the area under the curve,the diagnostic threshold,sensitivity and specificity were 0.760,-0.41,55.26,and88.24,respectively,of ?Kep predicting neoadjuvant chemotherapy efficiency after NAC2 cycle.Conclusion:1.Ktrans and Kep can evaluate the efficacy of NAC in advanced breast cancer.2.?Ktrans and ?Kep can predict the efficacy of NAC in advanced breast cancer patients in NAC early(2 cycles).The ?Kep change value has the highest prediction performance.3.Vp value can not assess and predict the efficacy of NAC.