Fig. 3From: Circulating tumor cells prior to initial treatment is an important prognostic factor of survival in non-small cell lung cancer: a meta-analysis and system reviewEvaluation of PFS with high or low abundance of CTCs by using meta-analysis (a-c) and systematic review (d). a Higher abundance of CTCs predicts shorter PFS of NSCLC. b Stratified study found that the differences of heterogeneity among tumor stages are quite small(I2 = 0%). c Stratified study found that the differences of heterogeneity among various detect methods of CTCs are moderate(I2 = 36.1%). d Systematic review of PFS (months) data indicated higher abundance of CTCs are asscociated with shorter PFSBack to article page