Figure 4.

Development and internal validation of an Elastic Net-Cox prognostic signature for mCRPC. (a) Ten-fold cross-validation profile of partial-likelihood deviance plotted against log(λ); vertical dashed lines denote λ.1se (green) and λ.min (yellow). (b) Regularization paths illustrating the shrinkage of individual coefficients as the penalty parameter increases. (c) Forest plot of hazard ratios and 95% confidence intervals from the multivariable Cox model incorporating Elastic Net-selected variables. (d) A three-predictor nomogram for estimating mCRPC-free survival probabilities at 365 and 545 days; individual predictor scores are summed to yield the total risk score and corresponding survival estimate. (e, f) Time-dependent receiver operating characteristic (ROC) curves assessing discriminative performance in the training cohort (e) and the validation cohort, respectively. (g) Kaplan-Meier survival estimates. (h) Calibration plots comparing predicted and observed mCRPC-free survival probabilities across both cohorts. (i) DCA evaluating the net clinical benefit.