Predictive Value Of MrTRS And Related ADC Value In Tumor Response After Neoadjuvant Therapy For Locally Advanced Rectal Cancer

Objective:Based on the MRI tumor response score(mrTRS)and related ADC values obtained by conventional MRI for rectal cancer,the tumor response after neoadjuvant chemoradiotherapy(n CRT)in locally advanced rectal cancer(LARC)was evaluated,and the value of the two in predicting tumor response was discussed.It provides a reference for the formulation and prognosis evaluation of personalized diagnosis and treatment plans for patients.Methods:Fifty-one patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy and postoperative resection in Shanxi People’s Hospital from January2020 to January 2023 were retrospectively collected.All patients underwent routine MRI examination before and after treatment.Patients with LARC were divided into two groups,namely good tumor response and poor tumor response,based on pathological tumor regression grade(p TRG).Clinical and imaging data of all patients were collected and image analysis was performed on sagittal T2WI,oblique T2WI-HR,DWI and ADC images before and after n CRT.Tumor length was measured,tumor signal intensity changes were observed,and relevant ADC values were measured by delineating the region of intest(ROI)of the largest cross-section of tumor in the same layer,and mrTRS scores were calculated comprehensively.Finally,statistics were made to study whether there were differences between the two groups before and after treatment,and whether the purpose of predicting tumor response could be achieved.SPSS 26.0 was used for statistical analysis in this study.Qualitative data were compared between groups using Chi-square test or Fisher exact probability method.Quantitative data were compared between groups by the two-independent T-test or the Wilcoxon rank sum test(which did not satisfy normality and homogeneity of variance).Binary logistic regression analysis was used to determine the influencing factors of tumor response after n CRT.The predictive performance of tumor response after n CRT and the combined predictive performance of all factors were analyzed using the receiver operating characteristic(ROC)curve.Kappa was used to describe the consistency between prediction methods.Test levelα=0.050.Results:A total of 51 patients were included in this study,including 18 patients in the good response group and 33 patients in the poor response group after rectal cancer n CRT.The ages of the two groups were 59.33±11.72 years and 60.39±8.36 years,respectively.There were 12(66.67%)and 26(78.79%)cases in males and 6(33.33%)and 7(21.21%)cases in females,respectively.The results of inter-group comparison showed that there were significant differences in pre-ADC(t=-5.362,P<0.001),post-N staging( ~2=5.023,P=0.040)and mrTRS score(u=3.263,P=0.001)between the two groups(P<0.050).Compared with the group with poor tumor response,the group with good tumor response had lower pre-ADC value,N stage and higher mrTRS score.Among them,pre-ADC and mrTRS scores were independent risk factors to distinguish two different tumor responses.The sensitivity,specificity,Yoden index and area under the curve of pre-ADC value and mrTRS score in predicting tumor response after n CRT were 75.76%,88.89%,63.65%,and 0.906,respectively.Conclusion:mrTRS score and related ADC values can accurately evaluate the response of colorectal cancer after n CRT therapy.pre-ADC value,mrTRS score and post-N staging are effective in accurately distinguishing good tumor response from poor tumor response,and the combined model of pre-ADC value and mrTRS score has the best performance in predicting different tumor response,which can provide a reliable diagnostic basis for selecting personalized treatment plan for rectal cancer patients before surgery.Combined with the prediction performance evaluation index,the results show that the pre-ADC+mrTRS combined prediction improves the prediction performance to a certain extent.