Introduction: The effect of temozolomide (TMZ) and radiotherapy (RT) in the treatment of glioblastoma (GBM) patients has been well documented in randomized controlled trials where the patients are selected. Here we present the effect of TMZ added to RT at a population level.
Methods: The Cancer registry of Norway (CRN) was searched for patients with a GBM diagnosis from 01.01.00 to 31.12.07. Subsequently, the prescriptions registered on these patients were obtained from the Norwegian prescription database (NPD). The data were first analyzed according to era (before/after the introduction of TMZ) and according to the treatment received. Furthermore, a matching procedure was utilized to reduce the bias between the RT+TMZ+ and RT+TMZ- groups so that the effect of TMZ could be better scrutinized.
Results: 1157 GBM patients were identified in total. The median overall survival (OS) was 8.3 (95% CI 7.6-9.0) and 10.1 (95% CI 9.1-11.0) months in the pre-TMZ and post-TMZ era, respectively (p<0.001). Analyzed according to treatment we found median OS for the RT-TMZ-, RT+TMZ- and TMZ+RT+ groups to be 2.5, 9.0 and 16.2 months, respectively (p<0.001). Two-year survival was 0%, 4% and 25%, respectively. The effect of age on TMZ was insignificant. In the matched group analysis TMZ provided a 7.6 month survival benefit.
Conclusions: Our population data reproduces the beneficial effect of TMZ from RCT´s with a median OS of 16.2 months and 25% 2-year survival. Furthermore, our population data indicate that TMZ might be effective also in elderly patients without contraindications.
Patient Care: This demonstrates the survival benefit of using temozolomide in the treatment of GBM patients.
Learning Objectives: That the effect of TMZ can be reproduced also at a population level with non-selected patients