Long-term experience with fractionated stereotactic radiotherapy in pharmacoresistant epilepsy: Neurological and MRI changes

SummaryPurposeRadiotherapy is an option in patients with difficult-to-treat epilepsy in which pharmacological and surgical alternatives have been exhausted. However, little is known about the long-term efficacy and side effects of radiotherapy in this context. Hence, we report for the first time on the long-term outcome (median 10 years) of fractionated stereotactic radiotherapy (FSRT) in 11 patients with drug-resistant epilepsy in a retrospective study. Primary endpoint is tolerability concerning neurological and MRI findings, secondary endpoint seizure frequency.Patients and methodsFSRT was performed in 11 patients with cryptogenic or symptomatic epilepsy from 1996 to 2009 using a conventional linear accelerator (LINAC) in seven cases and a dedicated NOVALIS® LINAC in four. The biologically equivalent dose ranged from 26.3 to 58.3 Gy (α/β = 10).Results(1) None of the patients developed temporary or permanent neurological deficits. No MRI changes occurred. (2)Treatment resulted in improvement of seizure frequency in seven patients, five of them had a decrease in seizure frequency, and two of them were seizure-free at last follow-up.ConclusionsIf radiation is administered with proper fractionation, dose prescription and target volume definition, long-term neurological side effects are unlikely. (2) Radiotherapy has the potential to control the frequency and intensity of seizures in epilepsy patients.