BACKGROUND: Epileptogenic glioblastomas are thought to convey a favorable 
prognosis, either due to early diagnosis or potential antitumor effects of 
antiepileptic drugs. We investigated the relationship between survival and 
epilepsy at presentation, early diagnosis, and antiepileptic drug therapy in 
glioblastoma patients.
METHODS: Multivariable Cox regression was applied to survival data of 647 
consecutive patients diagnosed with de novo glioblastoma between 2005 and 2013 
in order to investigate the association between epilepsy and survival in 
glioblastoma patients. In addition, we quantified the association between 
survival and valproic acid (VPA) treatment.
RESULTS: Epilepsy correlated positively with survival (HR: 0.75 (95% CI: 
0.61-0.92), P < .01). This effect is independent of age, sex, performance 
status, type of surgery, adjuvant therapy, tumor location, and tumor volume, 
suggesting that this positive correlation cannot be attributed solely to early 
diagnosis. For patients who presented with epilepsy, the use of the 
antiepileptic drug VPA did not associate with survival when compared with 
patients who did not receive VPA treatment.
CONCLUSION: Epilepsy is an independent prognostic factor for longer survival in 
glioblastoma patients. This prognostic effect is not solely explained by early 
diagnosis, and survival is not associated with VPA treatment.