| Objective:Assess the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion weighted imaging (DWI) in monitoring therapy effect of neoadjuvant chemotherapy(NAC) in patients with locally advanced breast cancer(LABC) and evaluating residual disease after NAC, to provide a reliable basis for judging prognosis and protocol making.Materials and methods:The prospective study included26lesions in24patients with LABC (UICC Stage II and III) undergoing NAC.MRI was examined before chemotherapy (the first time point),after the first cycle of chemotherapy(the second time point)and after all cycles(the third time point),including conventional Tl,T2weighted breast imaging,DCE-MRI and DWI(b=0s/mm2,800s/mm2). All patients were confirmed by pre-treatment core needle biopsy (CNB), and postoperative histopathological.25lesions were diagnosed as invasive ductal carcinoma, and one was mucinous breast carcinoma. By comparing pre-treatment FNAB and postoperative histopathological, all lesions were divided into the groups of pathological complete response (pCR) and non-pCR. The transverse maximum diameter, hemodynamic parameter (including early-phase enhancement rate of the first, second, and third minute), and apparent diffusion coefficient (ADC) was recorded and their changed values were measured, and then we had the tumor shrinkage rate.Paired-Samples T test were applied in comparison of parameters including the transverse maximum diameter, early-phase enhancement rate and ADC before chemotherapy and after the first cycle of chemotherapy, also above parameters before chemotherapy and after all cycles. Spearman's rank correlation coefficient was applied in evaluating correlation between the early-phase enhancement rate, ADC and the tumor shrinkage rate. Independent-samples t test were applied in comparison between pCR and non-pCR.Receiver operating characteristic curve (ROC) was drawn to compare the accuracies of the evaluations for pCR.Results:There was no statistical difference in early-phase enhancement rate and transverse maximum diameter (3.45±1.44cm,[1.52±0.51]X100%,[1.85±0.58]×100%,[1.92±0.56]×100%respectively) between the first and the second time point (t=2.033, p=0.054; t=0.441, p=0.663; t=-0.375, p=0.711; t=－0.976, p=0.338respectively). ADCmean and ADCmin after the first cycle ([1005.71±144.94] X10-6mm2/s,[820.04±250.54] X10-6mm2/s respectively) were significantly higher (t=－7.364, p=0.000; t=－5.719, p=0.000; t=-5.346, p=0.000) than the values before chemotherapy ([880.86±98.31] X10-6mm2/s,[716.62±257.79]×10-6mm2/s respectively). There was significant difference in aforesaid parameters between the first and the third time points (p<0.05)The transverse maximum diameter was correlated negatively with the tumor shrinkage rate, also early-phase enhancement rate on the third time point (p<0.05), and the changed values of early-phase enhancement rate and ADCmean on the third time point were positively with it (p<0.05). There was significant difference in ADCmean on the first time point between pCR and non-pCR (t=2.580, p=0.017;);. There were significant differences in early-phase enhancement rate of the second and third minute on the second time point between pCR and non-pCR (t=－2.418, p=0.024; t=－2.599, p=0.016).On the third time point, there are significant differences in the early-phase enhancement rate of the first, second, and third minute and tumor shrinkage (t=－2.761, p=0.011; t=－3.179, p=0.004; t=－2.983, p=0.006; t=－3.118, p=0.005respectively).We compared areas under curve (AUC) of ADC values, early-phase enhancement rates and tumor shrinkage rate for diagnosing as pCR by ROC. Tumor shrinkage rate had the best diagnostic capability among aforesaid parameters. Sensitivity and specificity of the diagnosis for pCR is84.6%and75.0%, as tumor shrinkage rate more than54.44%.Conclusion:ADC which is measured from DWI could be used to assess early response to NAC in breast cancer lesion, but not predict pCR or non-pCR for all cycles of chemotherapy on the first cycle.There is close relationship between the parameters in morphology and hemodynamic.The parameters in morphology, hemodynamic and functional imaging Tumor shrinkage rate could be evaluated by measuring the change values of parameters in morphology in some degree, hemodynamic and functional imaging. There is a lower average ADC (higher density of cells) in pCR than non-pCR before chemotherapy. There are significant differences in hemodynamic parameters between pCR and non-pCR after the first cycle of chemotherapy, even more obvious after all cycles. The chemotherapeutic efficacy could be diagnosised by measuring the change values of parameters in morphology, hemodynamic and functional imaging after all cycles of NAC, and tumor shrinkage rate is the best parameter for predicting effect. The early-phase enhancement rate of the third minute will be better than the first minute for predicting pCR as hemodynamic parameter. |
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