Glioblastoma is the most frequent primary malignant brain tumor. In daily practice and at whole country level, oncological care management for glioblastoma patients is not completely known.

To describe oncological patterns of care, prognostic factors, and survival for all patients in France with newly-diagnosed and histologically confirmed glioblastoma, and evaluate the impact of extended temozolomide use at the population level.

Nationwide population-based cohort study including all patients with newly-diagnosed and histologically confirmed glioblastoma in France in 2008 and followed until 2015.

Data from 2053 glioblastoma patients were analyzed (male/female ratio 1.5, median age 64 years). Median overall survival (OS) was 11.2 [95% confidence interval (CI) 10.7-11.9] months. The first-line therapy and corresponding median survival (MS, in months) were: 13% did not receive any oncological treatment (biopsy only) (MS = 1.8, 95% CI 1.6-2.1), 27% received treatment without the combination of radiotherapy (RT)-temozolomide (MS = 5.9, 95% CI 5.5-6.6), 60% received treatment including the initiation of the concomitant phase of RT-temozolomide (MS = 16.4, 95% CI 15.2-17.4) whom 44% of patients initiated the temozolomide adjuvant phase (MS = 18.9, 95% CI 18.0-19.8). Only 22% patients received 6 cycles or more of adjuvant temozolomide (MS = 25.5, 95% CI 24.0-28.3). The multivariate analysis showed that the risk of mortality was significantly higher for the non-progressive patients who stopped at 6 cycles (standard protocol) than those who continued the treatment, hazard ratio = 1.5 (95% CI 1.2-1.9).

In non-progressive patients, prolonging the adjuvant temozolomide beyond 6 cycles may improve OS.