Purpose: The phase II GLARIUS trial assigned patients with newly diagnosed, O-6-methylguanine-DNA methyltransferase promoter non-methylated glioblastoma to experimental bevacizumab/irinotecan (BEV/IRI) or standard temozolomide (TMZ). To identify subpopulations with a particularly favorable course, we assessed the prognostic potential of magnetic resonance imaging (MRI) markers before treatment onset.
Methods: MRIs at baseline (before treatment onset) were analyzed for T1-hyperintense and diffusion-restricted lesions; as well as the presence of both hyperintense and diffusion-restricted (double positive) lesions. The MRI findings were correlated with overall and progression-free survival.
Results: MRI scans were evaluable in 71% of the GLARIUS modified intention-to-treat population (n = 121 of 170; 88 patients in the BEV/IRI arm, and 33 patients in the TMZ control arm). Diffusion-restricted and T1 hyperintense lesions were present in 60% and 65% of patients in BEV/IRI arm, while 57% and 63% were found in the TMZ arm, respectively. Double positive lesions were found in 37% of BEV/IRI patients and in 39% of TMZ patients. Neither the presence of T1-hyperintense, diffusion-restricted lesions, nor double positive lesions were associated with improved survival.
Conclusions: Baseline T1-hyperintense and diffusion-restricted lesions are not suitable to predict progression-free or overall survival of patients treated with bevacizumab/irinotecan or temozolomide.
Keywords: Bevacizumab; Irinotecan; MRI; Newly diagnosed MGMT-non-methylated glioblastoma; Predictive and prognostic implications.