Detecting The Hight Risk Of Regional Lymph Node Metastasis After Neoadjuvant Chemoradiotherapy For Local Advanced Rectal Cancer And A Scoring System To Predict Its Involvement In Rectal Cancer

Objective:The aim of this study is to detect the high risk factor of regional lymph node metastasis after neoadjuvant chemoradiotherapy for local advanced rectal cancer(LARC)and establish a scoring system to predict its involvement before operation.Meanwhile,assessing the prognostic impact of patients with positive lymph node after neoadjuvant chemoradiotherpy(n CRT).Methods:A retrospective study was performed in the clinical variables of 409 patients with LARC who were treated at our institute between January 2009 and December 2014.There are 296 patients with no regional nodal involvement(yp N0)and 113 patients with regional lymph node metastasis(yp N+)confirmed by pathological report.In order to seek out the risk factor of regional lymph node metastasis after n CRT,we detect the clinical data by univariate and multivarite analysis,and construct a scoring system to identity possibly metastasizing lymph node.Evaluate the prognostic between yp N0 and yp N+ by Kaplan-Meier and compare the 5-year disease-free-survival(DFS)rate and 5-year overall survival(OS)rate by Log-rank.Results:1.Preoperative serum CEA?preoperative N stage assessed by ERUS and the long axis measured by ERUS were the unfavorable independent factors for regional nodal metastasis.The factors were incorporated into a scoring system and empowered scores according to the partial regression coefficient.Using receive operating characteristic(ROC)curve analysis and Youden's index,we determined a cutoff value of 8 for scores.When the scores calculated were equal or greater than 8,we consider that patients may suffer from regional metastasis.At which,the system's sensitivity was 73% and specificity 65%,the predictive validity of the scoring system was assessed on the testing sample,at which the system's sensitivity was 71% and specificity 62%.2.The median follow-up for was 24 months,and the total 5-DFS was 58%,5-OS 69.5%.Overall,the 5-DFS and 5-OS were 64.3% and 75.2% among yp N0 patients and 43.7% and 54.9% among yp N+ patients(P<0.001 and P=0.009).Conclusions:1.Preoperative serum CEA?preoperative N stage assessed by ERUS and the long axis measured by ERUS were the unfavorable independent factors for regional nodal metastasis.2.The prediction scoring system for regional lymph node metastasis would be benifitial in assessing the preoperative N stage,which may be contribute to select patients of organ-sparing management.3.Compared with yp N0 patients,the prognosis were worse among those with positive lymph node.