Survival Analysis The Impact Of The Number Of Removed Lymph Nodes On The Prognosis Of Esophageal Cancer

Objective: to analysis the independent prognostic factors of esophageal cancer,andevaluate the impact of NRLN on the advanced esophageal cancer prognosis.Methods: Clinical database was established from a retrospective analysis of173cases of patients with advanced esophageal squamous carcinoma postoperativeclinical data and follow-up results from January2009to September2010inUnion Hospital affiliated to Fujian Medical University.Thus established the clinicaldatabase. We selected10clinical characteristic factors; they are:sex, age, length oftumor, tumor location, tumor infiltration depth, the degree of differentiation, LNdissection areas, operation methods, NMLN and NRLN. Multivariate and univariateanalysis were performed respectively in order to obtain the esophageal cancerprognostic factors associated with long-term survival.And we particularly emphasizedthe effect of NRLN on postoperative3-year survival rate. SPSS19.0software wasused for statistical analysis.Results:3-years follow-up rate in our research was75.14%(130/173).The totalnumber of adopted cases was130, and3131LN were removed,including252positive LN,and the mean NRLN was24.08. Of these130patients,78patients werefound to have regional LNM with a LNM rate of60%.The3-year cumulative survivalrate of130cases was72.3%.We divided patients by the NMLN of0,1-2,3ormore.And the3-year cumulative survival rates were88.5%,69.8%,48.6%,respectively.Therefore we found NMLN was inverselyassociated with long-term survival. Univariate analysis in our study suggested that theprognostic factors of advanced esophageal cancer contained tumor length (P=0.016),the degree of differentiation (P=0.006), NMLN (P=0.001), and NRLN (P=0.02).Cox regression analysis revealed only NMLN(P=0.003) and the degree of tumordifferentiation (P=0.047) were statistically significant.Thus they two wereindependent prognostic factors.According to intraoperative NRLN,patients weredivided into group A(removed LN) and group B(removed LN).In group A tumorinfiltration depth and NMLN were not significantly correlated (P=0.837), while in group B the correlation were significant (P=0.005).By the NMLN of0,1-2,3-6,7ormore,we respectively divided A and B into4subgroups.Kaplan-Meier survival curveshowed there was no significant difference in survival rate between each subgroup ingroup A (P=0.076), while group B had the opposite result (P=0.005).In survivalanalysis, no significant difference was found between the prognosis of A and Bgroups（2=2.566，P=0.109）.According to intraoperative NRLN, patients weredivided into group C (removed LN=20-30) and group D (removed LN30).Kaplan-Meier survival curve showed that the survival rate of C groupwas significantly higher than that of D group (P=0.011).Conclusion:1. NMLN and the degree of tumor differentiation are the independentprognostic factors in patients with advanced esophageal cancer;2. If NRLN is onaverage less than20, positive LN will be missing,leading to underestimate the TNMstaging and affect the long-term survival;3. More LN removed does not necessarilymean the better survival rate. Prognosis might be negatively influenced when morethan30LN are removed.