Figure 2. Receiver operator characteristic (ROC) curves for N-R model and N stage as predictors of distant metastasis for all NPC patients (n = 719).

The area under the curve (AUC) was 0.663 for the N-R model (solid line) and 0.617 for clinical N stage (dotted line)(P = 0.015), indicating that the N-R model is a better predictor of distant metastasis.