Predictors of preoperative and early postoperative seizures in patients with intra-axial primary and metastatic brain tumors: A retrospective observational single center study.

Objective: Antiepileptic treatment of brain tumor patients mainly depends on the individual physician's choice rather than on well-defined predictive factors. We investigated the predictive value of defined clinical parameters to formulate a model of risk estimations for subpopulations of brain tumor patients.

Methods: We enclosed 650 patients > 18 years of age who underwent brain tumor surgery and included a number of clinical data. Logistic regressions were performed to determine the effect sizes of seizure-related risk factors and to develop prognostic scores for the occurrence of preoperative and early postoperative seizures.

Results: A total of 492 patients (334 gliomas) were eligible for logistic regression for preoperative seizures, and 338 patients for early postoperative seizures. Age ≤ 60 years (odds ratio [OR] = 1.66, p = 0.020), grades I and II glioma (OR = 4.00, p = 0.0002), total tumor/edema volume ≤ 64cm(3) (OR = 2.18, p = 0.0003), and frontal location (OR = 2.28, p = 0.034) demonstrated an increased risk for preoperative seizures. Isocitrate-dehydrogenase mutations (OR = 2.52, p = 0.026) were an independent risk factor in the glioma subgroup. Age ≥ 60 years (OR = 3.32, p = 0.041), total tumor/edema volume ≤ 64cm(3) (OR = 3.17, p = 0.034), complete resection (OR = 15.50, p = 0.0009), diencephalic location (OR = 12.2, p = 0.013), and high-grade tumors (OR = 5.67, p = 0.013) were significant risk factors for surgery-related seizures. Antiepileptics (OR = 1.20, p = 0.60) did not affect seizure occurrence. For seizure occurrence, patients could be stratified into 3 prognostic preoperative and into 2 prognostic early postoperative groups.

Interpretation: Based on the developed prognostic scores, seizure prophylaxis should be considered in high-risk patients and patient stratification for prospective studies may be feasible in the future.