Figure 2.

Survival analysis for the base and extended multivariate models on the combined cohorts. Kaplan–Meier analysis of overall survival (OS) with stratification into lower- and higher-risk groups (the higher and lower curves, respectively) based on maximized statistical separation in terms of the log-rank test statistic (P < .001), for the base 4-variable clinical model comprised age, hypoxic volume (HV), T/Bmax (maximal activity voxel in a tissue region normalized by the blood activity) and SUVpeak (average SUV from a 1-cm circular ROI centered over the hottest voxel; dashed red lines), and its extension using additional radiomic features (solid blue lines). The figure shows how the latter model led to different patient classification.