Combined imaging- and gene-based biomarker. Kaplan-Meier curves for progression-free survival (PFS) of 77 patients with a more or less hypoxic tumour classified by imaging (a) or genes (b), and for the three classification groups defined in Fig. 2c (c). (d) Correlation plot of biomarker values for the same 77 patients, showing gene-defined versus imaging-defined hypoxia. The optimal line for classifying patients with a more (above the line) and less (below the line) hypoxic tumour to achieve the strongest association to PFS is shown. (e, f) Kaplan-Meier curves for PFS of patients classified into the two groups defined in (d) for the 77 patients used to define the line (e), and the 41 remaining patients (f). P-values from log-rank test, number of patients at risk, 60-month recurrence probability and HR with 95% CIs are indicated in the Kaplan-Meier plots.