NIMG-40MRI TUMOR PROGRESSION PATTERNS IN THE GLARIUS TRIAL

Abstract

BACKGROUND: We evaluated patterns of tumor progression in patients with primary glioblastoma who were assigned to undergo treatment with bevacizumab/irinotecan (BEV/IRI) versus standard temozolomide (TMZ) within the randomized phase II GLARIUS trial. METHODS: In 160 patients (106 BEV/IRI, 54 TMZ), we reviewed magnetic resonance imaging (MRI) scans at baseline and tumor progression. Based on contrast-enhanced T1-weighted and fluid-attenuated inversion recovery (FLAIR) images we assessed tumor patterns and invasiveness. Tumor patterns were classified as either multifocal or local at baseline and progression; at progression, we additionally assessed whether distant lesions appeared. Invasiveness was determined as either diffuse or non-diffuse. Associations were calculated using Fisher's exact test. RESULTS: At baseline, 118 of 160 evaluable patients (73.8%) had a locally confined tumor. In the BEV/IRI arm 10% and in the TMZ arm 8% of patients with an initially local tumor growth changed to a multifocal pattern (p = 0.78); distant lesions were found in 24% in the BEV/IRI arm and 19% in the TMZ arm (p = 0.55). 8% of patients in the BEV/IRI arm and 11% in the TMZ arm developed a diffuse growth pattern from an initially non-diffuse pattern (p = 0.58). CONCLUSIONS: The tumor progression and invasiveness patterns do not differ between BEV/IRI and TMZ-treated patients in the GLARIUS trial. BEV/IRI did not increase the rate of multifocal, distant or highly invasive tumors at the time of progression.