Management and outcomes of glioblastoma: 20-year experience in a single Australian institution.

INTRODUCTION:We aimed to evaluate the changing patterns in the management of glioblastoma (GBM) and impact on survival outcomes over a 20-year period. METHODS:This is a retrospective study of patients diagnosed with GBM between 2001 and 2020, who had radiation therapy (RT) in an Australian institution. The primary outcomes were changes in treatment modalities (including surgery, RT, and chemotherapy) over time and overall survival (OS). Multivariable Cox regressions were used to evaluate factors associated with OS, including age, sex, ECOG performance status, treatment modalities, treatment facility, and year of treatment. RESULTS:1079 patients were included in this study. Thirty-five per cent of patients had gross total resection, increasing from 31% in 2001-2005 to 45% in 2016-2020 (P < 0.001). Sixty-four per cent of patients had ≥60 Gy RT, increasing from 57% in 2001-2005 to 66% in 2016-2020 (P < 0.001). Seventy-five per cent of patients had chemotherapy, increasing from 22% in 2001-2005 to 89% in 2016-2020 (P < 0.001). Treatment received varied based on patients' age and ECOG performance status. The median OS for the entire cohort was 13.0 months (95% CI = 12.0-13.7). Median OS in patients who had maximal treatment (i.e., gross total resection, ≥60 Gy RT and chemotherapy) was 20.6 months (95% CI = 17.3-22.8). In multivariable analyses, age, sex, treatment facility, extent of surgical resection, RT dose, and chemotherapy use were associated with OS. CONCLUSION:This is one of the largest Australian series on the management and outcomes of GBM spanning a 20-year period. We observed improvement in OS over time, which is likely associated with evolving treatment options over the study period.