Fig. 1.
Predictors in the final multivariable model, using transformed variables to simplify the model. No regression coefficients are estimated for the treatment cohorts as overall survival is estimated by the Kaplan-Meier method for the strata (treatment cohorts). EQD2 = equivalent dose in 2-Gy fractions; GTV = gross tumor volume; OTT = overall treatment time; WHO-PS = World Health Organization performance status.