Epilepsy surgery related to pediatric brain tumors: Miami Children's Hospital experience

Abstract

Object: Pediatric brain tumors may be associated with medically intractable epilepsy for which surgery is indicated. The authors sought to evaluate the efficacy of epilepsy surgery for seizure control in pediatric patients with brain tumors.

Methods: The authors performed a retrospective review of consecutive patients undergoing resective epilepsy surgery related to pediatric brain tumors at Miami Children's Hospital between June 1986 and June 2014. Time-to-event analysis for seizure recurrence was performed; an "event" was defined as any seizures that occurred following resective epilepsy surgery, not including seizures and auras in the 1st postoperative week. The authors analyzed several preoperative variables to determine their suitability to predict seizure recurrence following surgery.

Results: Eighty-four patients (47 males) with a mean age (± standard deviation) of 8.7 ± 5.5 years (range 0.5-21.6 years) were included. The study included 39 (46%) patients with gliomas, 20 (24%) with dysembryoplastic neuroepithelial tumors (DNETs), 14 (17%) with gangliogliomas, and 11 (13%) with other etiologies. Among the patients with gliomas, 18 were classified with low-grade glioma, 5 had oligodendroglioma, 6 had uncategorized astrocytoma, 3 had pilocytic astrocytoma, 3 had pleomorphic xanthoastrocytoma, 3 had glioblastoma, and 1 had gliomatosis cerebri. Seventy-nine (94.0%) resections were guided by intraoperative electrocorticography (ECoG). The mean time (± standard deviation) to seizure recurrence was 81.8 ± 6.3 months. Engel Class I outcome was achieved in 66 (78%) and 63 (75%) patients at 1 and 2 years' follow-up, respectively. Patients with ganglioglioma demonstrated the highest probability of long-term seizure freedom, followed by patients with DNETs and gliomas. In univariate analyses, temporal location (HR 1.75, 95% CI 0.26-1.27, p = 0.171) and completeness of resection (HR 1.69, 95% CI 0.77-3.74, p = 0.191) demonstrated a trend toward a longer duration of seizure freedom.

Conclusions: ECoG-guided epilepsy surgery for pediatric patients with brain tumors is highly effective. Tumors located in the temporal lobe and those in which a complete ECoG-guided resection is performed may result in a greater likelihood of long-term seizure freedom.

Keywords: AED = antiepileptic drug; DNET = dysembryoplastic neuroepithelial tumor; ECoG = electrocorticography; EEG = electroencephalography; ETANTR = embryonal tumor with abundant neuropil and true rosettes; EZ = epileptogenic zone; FCD = focal cortical dysplasia; LGG = low-grade glioma; TTE = time to event; oncology; pediatric brain tumor; resective epilepsy surgery; seizure freedom; time to event.