‘The epileptology of primary brain tumours’: A study of the nature and impact of epilepsy, seizure outcome and the feasibility of using t ranscranial magnetic s timulation as a biomarker of treatment res po nse in patients with a primary brain tumour.

Abstract

Primary brain tumours (PBT) have a significant impact on cognition, mood and quality of life. An epileptic seizure, which is very common in this group of patients, produces further deterioration in already vulnerable patients with a brain tumour. There is a subset of patients with low-grade glioma who present intractable epilepsy. Currently, there is no biomarker to suggest who will develop epilepsy or intractable epilepsy, and to recommend who should continue with antiepileptic drugs (AED), and for how long, following resection of the PBT. Patients with high-grade glioma are generally treated with radiotherapy, chemotherapy and corticosteroid. Continuing AED may have serious interactions with these treatments. Although invasive electroencephalogram (iEEG) monitoring is a well-established additional investigation in patients with non-lesional focal epilepsy for identification of an epileptogenic zone, use of iEEG monitoring in lesional epilepsy is not well studied and may cause serious complications. In this prospective study, I will look at the prevalence of epilepsy in patients with a PBT, and correlate the occurrence of seizures with histopathology, World Health Organisation grading and magnetic resonance imaging location. I will examine the impact of epilepsy on cognition, mood and quality of life. I will explore the seizure outcome following resection of the PBT longitudinally to investigate the relationship of seizure recurrence and intractable epilepsy with tumour recurrence, oncological treatment and ongoing AED use. I will perform transcranial magnetic stimulation to examine cortical excitability to find biomarkers, which could predict the occurrence of seizures, intractable epilepsy and treatment response. This will support a rational management plan to minimise adverse drug interactions and improve the quality of life in patients with PBT related epilepsy. Finally, I will examine the indications and complications of invasive EEG monitoring to justify the use of iEEG monitoring in PBT related epilepsy.