Retrospective single-center study on elderly patients with glioblastoma between 2014 and 2018 evaluating the effect of age and performance status on survival.

Background: Incidence of glioblastoma (GBM) increases with age and the prognosis is worse among the elderly. This was shown in a Finnish population-based register study evaluating GBM patients diagnosed between 2000 and 2013. The median overall survival (OS) was poor among the elderly (4.5 months), despite the OS increase during that period. We conducted a study to see if the OS has increased in our hospital area with current therapies. Methods: One hundred and ninety-eight patients over 65 years at the time of diagnosis, with malignant glioma diagnosed January 1, 2014 to December 31, 2018 at the Helsinki Comprehensive Cancer Center were included. In addition to grade IV gliomas, grade III gliomas with nonmutated R132HIDH1 and only radiographically diagnosed gliomas were included. The demographics and treatment data were collected with performance status evaluated retrospectively. The Kaplan-Meier method and the multivariate Cox proportional hazard model were used for the statistical analysis. Results: One hundred and seventy-seven patients with grade IV glioma, 6 with grade III glioma with nonmutated IDH1 and 15 radiologically diagnosed patients were included. One hundred and sixteen patients received chemoradiation, 59 only radiotherapy, 3 only temozolomide, and 27 patients did not receive oncological treatments. In the age group 65-70 years the OS was 9.95 months, 70-75 years 10.12 months, and >75 years 5.54 months. Lower WHO status correlated with longer survival independently of the age of the patient. Also methylated O(6)-methylguanine-DNA-methyltransferase and tumor resection correlated with better survival. Conclusions: The performance status of elderly patients is the most important prognostic factor. When choosing treatment protocols for patients in this age group, the performance status not calendar age should be considered.