Association Analysis Of MrTRG And Prognosis In Locally Advanced Rectal Cancer After Neoadjuvant Chemoradiotherapy

Obective:To retrospectively analyze the magnetic resonance Tumor Regression Gra-de(mrTRG)and Pathological Tumor Regression Grade(pTRG)of patients with loca-lly advanced rectal cancer(LARC)after long-term neoadjuvant chemoradiotherapy(NCRT).to explore the feasibility of nrTRG as a prognostic predictor of LARC patients.Methods:Fifty-three patients who were evaluated as LARC by magnetic resonance imaging were selected from the Surgical Oncology Department of the First Affiliated Hospital of Kunming Medical University from January 2009 to December 2017.All patients received NCRT before operation.Six to eight weeks after neoadjuvant chemoradiotherapy,magnetic resonance imaging was done again and total mesorectal excision(TME)was performed,magnetic resonance imaging was used to evaluate T stage,lymph node(N)stage,mesorectal Fascia(MRF)status,extramural vascular invasion(EMVI)status before and after NCRT,as well as mrTRG after neoadjuvant chemoradiotherapy.Pathological evaluation of T stage,N stage and pTRG after operation was performed on gross specimens.In the magnetic resonance imaging examination after treatment,mrTRG was divided into 5 grades,pTRG was divided into groups by Mandard 5 grades,TRG1-2 was defined as good response group,TRG3-5 was defined as bad response group,and magnetic resonance T stage and pathological T stage were divided into groups T0,Tis,T1,T2 were defined as good response group,T3 and T4 were defined as bad reaction group;the relationship between the above data and prognosis was analyzed.The consistency of mrTRG and pTRG results was tested by kappa value,the accuracy of mrTRG and pTRG results was tested by ROC curve,survival rate was calculated by Kaplan-Meier method,survival curve was drawn,and survival-related prognostic factors were counted by Tarone-Ware method.Cox proportional risk model was used to analyze the influencing factors related to 5-year overall survival(OS).P<0.05 was considered to be statistically significant.Results:Fifty-three cases were enrolled,42 males(81.2%)and 11 females(20.8%);22 cases(41.5%)were older than 60 years old and 31 cases(58.5%)were younger than 60 years old,with a mean age of 56±10.0 years,ranging from 33 to 77 years;the shortest follow-up time was 11 months,the longest was 100 months,and the median follow-up time was 31 months(19.0,53.5).The 5-year overall survival rate was 83%,the 2-year disease-free survival rate was 67.9%,the 2-year local recurrence rate was 13.2%,and the 2-year distant metastasis rate was 18.9%.During the follow-up period,7 patients(13.2%)died due to tumor factors.A total of 18 cases had local recurrence and distant metastasis,10 cases(18.9%)had distant metastasis,including 6 cases(11.3%)of lung metastasis,2 cases(3.8%)of liver metastasis,1 case(1.9%)of bone metastasis,1 case(1.9%)of multisite distant metastases,4 cases(7.5%)of local recurrence and multi-site distant metastases.Metastasis occurred in 4 cases(7.5%).The consistency test results of mrTRG and pTRG showed that the kappa value was 0.632,indicating that the results of mrTRG and pTRG were highly consistent.The area under the ROC curve of mrTRG and pTRG was 0.70,which indicated that the accuracy of predicting pTRG by mrTRG was good;univariate analysis showed that after treatment,N status,MRF status,EMVI status,mrTRG,ypN and pTRG were correlated with 5-year overall survival(OS),P<0.05;T stage,N status,MRF status,EMVI status,MRTRG status,EMVI status after neoadjuvant chemoradiotherapy and mrTRG status were correlated with 5-year overall survival(OS),P<0.05;after treatment,T stage,N status,MRF status,EMVI status,ypN,pathological T stage(ypT),pTRG were correlated with disease free survival(DFS)in 2 years,P<0.05;after treatment,N stage,EMVI status,pTRG were correlated with local recurrence(LR)in 2 years,P<0.05;before treatment,EMVI status,T stage,N stage,MRF state,EMVI status,TRGS ypT,pTRG were correlated with distant metastasis in 2 years,P<0.05.COX multivariate regression analysis showed that mrTRG(P=0.016,RR=4.028)and EMVI status after neoadjuvant chemoradiotherapy(P=0.037,RR=25.422)were independent risk factors for OS at 5 years.mrTRG RR>EMVI status RR showed that mrTRG had greater impact on OS.Conclusions1.The results of mrTRG and pTRG after Neoadjuvant Chemoradiotherapy are highly consistent,and the accuracy of predicting pTRG by mrTRG is good.2.magnetic resonance imaging after neoadjuvant chemoradiotherapy for locally advanced rectal cancer was evaluated as a poor combination of mrTRG and a poor prognosis in patients with positive extramural vascular invasion after treatment.3.mrTRG and EMVI status after neoadjuvant chemoradiotherapy can be used as predictors for patients with locally advanced rectal cancer.