Fig. 5

Assessment of publication bias using Funnel plot analysis. a-b Funnel plot analysis of studies on OS ((a) LODDS1 vs. LODDS0, b LODDS2 vs. LODDS0). c-d Funnel plot analysis of studies on DFS ((c) LODDS1 vs. LODDS0, d LODDS2 vs. LODDS0). Publication bias was not found in the meta-analyses of OS and DFS. All of the funnel plots of the included articles showed a symmetrical distribution. Thus, no significant publication bias was found in the meta-analyses of OS or DFS. HR, hazard ratio; OS, overall survival; DFS, disease-free survival; LODDS, log odds of positive lymph nodes