Model validation and clinical use
The predictive capability of the nomogram was evaluated by assessing discrimination power and calibration in the training, validation, and entire cohorts. The concordance index (C-index) was computed to evaluate the discriminative ability of the novel nomogram in all cohorts. A higher C-index suggests superior capability to differentiate patients according to survival status. Calibration curve produced from 1000 bootstrap replicates was used to examine the conformity between the model-predicted probability and the actual condition. In addition, to further evaluate the predictive performance of the nomogram for OS, ROC curve was plotted over the total score of the nomogram for OS for each patient, and AUC analyses was computed. Finally, the net benefit of the novel nomogram was measured with decision curve analysis (DCA).