Analysis Of Factors Related To Complete Pathological Remission After Neoadjuvant Treatment Of Locally Advanced Rectal Cancer

OBJECTIVE:The currently accepted gold standard for the treatment of locally advanced rectal cancer is preoperative neoadjuvant chemoradiotherapy combined with total mesorectal excision.Neoadjuvant chemoradiation can effectively reduce the tumor staging of patients,improve the anus preservation rate and the R0 resection rate,and reduce the local recurrence rate.However,there are individual differences in the efficacy of neoadjuvant therapy.Only some patients can obtain pCR after neoadjuvant therapy combined with radical surgery,and patients with pCR have a better survival prognosis.The purpose of this article is to study and analyze the relevant clinical factors affecting pCR after neoadjuvant treatment of locally advanced rectal cancer,and guide the clinical development of individualized treatment plans.Methods:A retrospective analysis of data from 62 patients with locally advanced rectal cancer evaluated by pelvic MRI and colonoscopy from December 2017 to November 2019 in the Department of Oncology and Radiotherapy of the First Affiliated Hospital of Kunming Medical University.All patients received neoadjuvant treatment before surgery.Pelvic MRI and total mesorectal excision were performed 6-8 weeks after the end of chemoradiotherapy.Multivariate logistic regression analysis was used to explore the independent influencing factors of the variables,and p?0.05 considered that the difference was statistically significant.Kappa value was used to test the consistency of mrTRG and pTRG results,and the ROC curve was drawn to determine the accuracy of mrTRG to evaluate the complete remission of pathology,and the best cutoff value,sensitivity and specificity were calculated.Results:A total of 62 cases were included in this study.A total of 18 cases of pCR were obtained after neoadjuvant therapy(18/62,29%).Seven factors including age,gender,T stage before treatment,N stage before treatment,CRM,EMVI,and MRI were included in this study.Univariate analysis showed that T stage before treatment(P=0.02)and MRI type(P=0.01)were related to pCR rate after neoadjuvant therapy for locally advanced rectal cancer.The results of multivariate analysis showed that T stage(OR=0.15,P=0.03),CRM(OR=0.25,P=0.05),and MRI type(OR=4.59,P=0.02)were important factors affecting pCR obtained after neoadjuvant therapy for locally advanced rectal cancer.Kappa analysis results showed that mrTRG and pTRG had a high degree of consistency(Kappa=0.8),and ROC curves were plotted.The results showed that AUC=0.92,sensitivity 72.22%,and specificity 95.46%.Conclusions:1.Neoadjuvant therapy can increase the pCR rate of locally advanced rectal cancer.Tumor T stage,CRM and MRI classification have important predictive effects on pCR after neoadjuvant therapy.Tumor low T stage,CRM negative and invasive type patients with locally advanced rectal cancer have a higher pCR rate.2.There is good consistency between mrTRG and pTRG classification,which can effectively judge the response of neoadjuvant treatment of locally advanced rectal cancer and play an important role in making treatment decisions for patients.