Validation of the nomogram
In the development cohort, the calculated C-index of the generated nomogram for patient OS was 0.751 (0.737–0.765), which was more significant than that of the 7th AJCC stage 0.681 (0.665–0.697). Additionally, the performances of the nomogram were assessed by ROC curves, with AUC values of 0.845, 0.808 and 0.800 for 1-year, 3-year and 5-year OS, respectively (Fig. ROC curves of the nomogram for 1-year, 3-year and 5-year OS in development cohort (Calibration plots of development cohort for 1-year(Decision curve analysis of nomogram and AJCC 7