Baseline T1 hyperintense and diffusion-restricted lesions are not linked to prolonged survival in bevacizumab-treated glioblastoma patients of the GLARIUS trial.

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.

Tumor growth patterns of MGMT-non-methylated glioblastoma in the randomized GLARIUS trial.

BACKGROUND: We evaluated patterns of tumor growth in patients with newly diagnosed MGMT-non-methylated glioblastoma who were assigned to undergo radiotherapy in conjunction with bevacizumab/irinotecan (BEV/IRI) or standard temozolomide (TMZ) within the randomized phase II GLARIUS trial. METHODS: In 142 patients (94 BEV/IRI, 48 TMZ), we reviewed magnetic resonance imaging scans at baseline and first tumor recurrence. Based on contrast-enhanced T1-weighted and fluid-attenuated inversion recovery images, we assessed tumor growth patterns and tumor invasiveness. Tumor growth patterns were classified as either multifocal or local at baseline and recurrence; at first recurrence, we additionally assessed whether distant lesions appeared. Invasiveness was determined as either diffuse or non-diffuse. Associations with treatment arms were calculated using Fisher's exact test. RESULTS: At baseline, 115 of 142 evaluable patients (81%) had a locally confined tumor. Between treatment arms, there was no significant difference in the fraction of tumors that changed from an initially local tumor growth pattern to a multifocal pattern (12 and 13%, p = 0.55). Distant lesions appeared in 17% (BEV/IRI) and 13% (TMZ) of patients (p = 0.69). 15% of patients in the BEV/IRI arm and 8% in the TMZ arm developed a diffuse growth pattern from an initially non-diffuse pattern (p = 0.42). CONCLUSIONS: The tumor growth and invasiveness patterns do not differ between BEV/IRI and TMZ-treated MGMT-non-methylated glioblastoma patients in the GLARIUS trial. BEV/IRI was not associated with an increased rate of multifocal, distant, or highly invasive tumors at the time of recurrence.