A population-based cohort study of glioblastoma (WHO grade 4 gliomas) in Ontario: continued improvement in care over 25 years

Objective — Grade 4 glioma is the most common and fatal primary malignant brain tumor in adults. We sought to describe the evolution of patient care and survival of glioblastoma patients in a single-payer Canadian provincial healthcare system over a 24-year period.

Methods — Adult patients >18 years of age with pathologically or clinically diagnosed glioblastoma (based on 4th or earlier edition of WHO classification) in Ontario between 1994 and 2018 were identified and followed until death or study endpoint of two years through provincial administrative health data. Patient characteristics, type of treatment, survival, and time spent in hospital were compared across time periods, age groups, and centers.

Results — We included 9,487 glioblastoma patients treated from 1994 to 2018. Median survival and 2-year survival rate improved over the study period from 6.4 to 9.4 months and 10% to 18% respectively. Older age was associated with shorter survival (median survival of 12 months at 65-74 years vs. 3 months >85 years), less aggressive therapy, and a higher proportion of remaining lifetime spent in hospital (>1/3 of patients > 75 years spend ≥50% their remaining survival in hospital). Time in hospital dropped by 8.9 days (95%CI 8.53-9.25) over the study period. Significant heterogeneity exists in patient management and outcome between regional treatment centers.

Conclusions — The real-world prognosis for grade 4 glioma remains poor. However, an increased proportion of patients receiving maximal therapy is associated with a small but meaningful improvement in survival and decreased time in hospital, for all but the most elderly patients.