Antiseizure medications can affect survival in glioblastoma
Patients with glioblastoma—the most common and most malignant form of brain tumor in adults—may live longer if they take valproic acid rather than another type of agent to control seizures, suggest the results of a recent study.
Seizures occur in up to half of patients with glioblastomas, and the use of antiepileptic drugs (AEDs) is highly recommended for this population. Researchers with the European Organization for Research and Treatment of Cancer and the National Cancer Institute of Canada Clinical Trials Group analyzed the use of antiepileptic agents in 573 persons with glioblastomas participating in a clinical trial evaluating radiation therapy with and without temozolomide. (Radiation therapy and chemotherapy with temozolomide is standard postsurgical treatment for persons with newly diagnosed glioblastoma.)
At the start of treatment, 175 patients were taking no AED. Of the 398 patients who were taking an AED, 97 were using valproic acid as their only such medication. Although overall survival was similar between the group that was taking an AED at baseline and the group that was not, patients taking valproic acid alone lived an average of 3 months longer than those taking another AED or those not receiving any antiepileptic medication. This survival benefit was not seen in valproic acid users who received radiation therapy without temozolomide.
The valproic acid-only users had more grade 3 and grade 4 thrombopenia and leukopenia than other patients.
“Despite some limitations, our results suggest that the choice of seizure medications in brain tumor patients should be carefully considered as it may give people a few more months with their loved ones,” noted study author Michael Weller, MD, a neurologist at the University Hospital Zurich (Switzerland), in a statement describing his team's findings.
In their report for Neurology, Weller and colleagues concluded that studies are needed to determine whether valproic acid increases temozolomide bioavailability or acts as an inhibitor of histone deacetylases, thereby sensitizing radiochemotherapy in vivo.