Prognostic factors for survival in adult patients with recurrent glioblastoma: a decision-tree-based model

We assessed prognostic factors in relation to OS from progression in recurrent glioblastomas. Retrospective multicentric study enrolling 407 (training set) and 370 (external validation set) adult patients with a recurrent supratentorial glioblastoma treated by surgical resection and standard combined chemoradiotherapy as first-line treatment. Four complementary multivariate prognostic models were evaluated: Cox proportional hazards regression modeling, single-tree recursive partitioning, random survival forest, conditional random forest. Median overall survival from progression was 7.6 months (mean, 10.1; range, 0–86) and 8.0 months (mean, 8.5; range, 0–56) in the training and validation sets, respectively (p = 0.900). Using the Cox model in the training set, independent predictors of poorer overall survival from progression included increasing age at histopathological diagnosis (aHR, 1.47; 95% CI [1.03–2.08]; p = 0.032), RTOG–RPA V–VI classes (aHR, 1.38; 95% CI [1.11–1.73]; p = 0.004), decreasing KPS at progression (aHR, 3.46; 95% CI [2.10–5.72]; p