Table 3 Random Forest models for overall survival prediction. C-index results are presented for each combination of variables in the training and test cohorts

GEP_0.01

0.5934

0.6301

GEP_0.05

0.7530

0.6649

GEP_0.1

0.7783

0.7415

Age, Gender, Stage

0.6340

0.6202

Age, Gender, Stage, COO

0.6761

0.6837

Age, Gender, Stage, 4-gene expression cluster

0.6725

0.6971

Age, Gender, Stage, COO, 4-gene expression cluster

0.7059

0.7221

GEP_0.1, 4-gene expression cluster

0.7792

0.7558

GEP_0.1, COO

0.7784

0.7487

Age, Gender, Stage, GEP_0.1

0.7788

0.7522

Age, Gender, Stage, GEP_0.1, 4-gene expression cluster

0.7889

0.7416

Age, Gender, Stage, GEP_0.1, COO

0.7854

0.7538

Age, Gender, Stage, COO, GEP_0.1, 4-gene expression cluster

0.7896

0.7596

Age, Gender, Stage, COO, GEP_0.1, 4-gene expression cluster

(parameter optimized)

0.8051

0.7615

Age, Stage, COO, 4-gene expression cluster, 50 genes

(variable reduction, parameter optimization)

0.8404

0.7942