The Role Of Forecasting Curative Effect On The Diffusion-weighted Magnetic Resonance Imaging In The Preoperative Chemradiotherapy For Locally Advanced Rectal Cancer

Objective:To explore the role of forecasting curative effect on the DWI in the preoperative chemradiotherapy?CRT?for locally advanced rectal cancer?LARC?.Methods:44 cases of the LARC patients confirmed by colonoscope biopsy pathology were involved in the analysis from June 2016 to December 2017.All patients were examined by the regular MRI which including the DWI series before or after the CRT.The apparent diffusion coefficient?ADC?of the pre/post CRT were tested for all patients.According to the efficacy of neoadjuvant radiotherapy and chemotherapy,patients were divided into T-downstaged group and T-non-downstaged group,pCR group and non-pCR group.We compared the pre/post chemoradiotherapy and the difference among the ADC value between groups,the ADC variation between groups??ADC?and the change rate of ADC?ADC%?,and according to the ROC curve,we obtained the optimal critical value of ADC for curative effect forecasting.Results:Among the 44 cases of the patients,7patients?account for 15.9%?were in pathological complete response,with 24 cases in T-downstaged group and 20 cases in T-non-downstaged group respectively.The ADCs of the pre/post CRT from 44 patients were 0.82±0.16,1.22±0.19(×10^-3mm²/s)respectively,which difference was statistically significant?P<0.001?;the ADC value of the pre CRT in T-downstaged group was significantly lower than that of the T-non-downstaged group?0.76±0.09 vs.0.90±0.20?×10^-3mm²/s,which difference was statistically significant higher than that of T-non-downstaged group?1.29±0.19 vs.1.14±0.15?×10^-3mm²/s,which difference was statistically significant?P=0.005?;before concurrent radiotherapy and chemotherapy,the ADC value of pCR group was significantly lower than that of non-pCR group?0.71±0.08 vs.0.84±0.17?×10^-3mm²/s.After concurrent radiotherapy and chemotherapy,the ADC value of pCR group was significantly higher than that of non-pCR group?1.42±0.27 vs.1.18±0.14?×10^-3mm²/s,with statistical significance?P<0.005?;the?ADC and the ADC%of the post?P=0.007?;the ADC value of the post CRT in T-downstaged group was significantly CRT in T-downstaged group were both significantly higher than that ofT-non-downstaged group,which difference was statistically significant?Z=-5.53,P<0.001;P=-5.09,P<0.001?.Conclusion;The quantitative analysis of the ADC was able to forecast the sensitivity of the CRT from rectal cancer patients in early stage,create certain value of the pre-CRT judgement,and facilitate the implementation of individualized treatment.