Figure 1a: ROC curve of increasing rate of tumor burden predicting mortality at progression according to the WHO criteria. The area under the ROC curve was 0.69 (95% CI: 0.43, 0.95). Increase in the SPD of at least 54% is predictive of mortality at progression with a sensitivity of 67% (42%, 87%) and a specificity of 50% (9%, 91%).