The current study aimed to perform a comprehensive meta-analysis to investigate the correlation of isocitrate-dehydrogenase 1 (IDH1), an important molecular biomarker for glioma classification and prognosis, to preoperative seizure incidence in LGG.
Isocitrate dehydrogenase 1 and 2 mutations (IDH1/2) have an established association with preoperative seizures in patients with grades II-IV diffuse gliomas.
There was a significant difference in seizure incidence between the IDH1 mutation group (61.6%) and wild-type IDH1 group (32.1%) (odds ratio 2.76; 95% confidence interval, 1.26-6.02; I<sup>2</sup> = 73%; P = 0.01).
Among the WHO grade II and III gliomas, IDH1 mutations were significantly associated with preoperative seizures, but no significant relationship between IDH mutations and preoperative seizures was found with glioblastoma multiforme.
Meta-regression analysis showed preoperative seizure OR was not related with preoperative seizure incidence (t=0.37, P=0.736), and not related with IDH1 mutation rate (t=1.85, P=0.162).
However, IDH1/2 mutation does not seem to contribute to the seizure control postoperatively (P=0.350 and 0.577 for the 6- and 12-month follow-up, respectively, chi-squared test).
Thirty-one of 52 patients (60%) with a preoperative history of seizures had an IDH1 mutation (p = 0.02), and 15 of 22 patients (68.2%) who experienced intraoperative seizures had an IDH1 mutation (p = 0.03).
The GBMO group showed more frequent tumor-related seizures (P= .027), higher frequency of IDH1 mutation (31% vs. <5%, P= .015), lower MGMT expression (P= .016), and longer survival (19.0 vs. 13.2 months; P= .022).
Molecular genetic abnormalities identified in 17 cases were IDH1 mutation (n = 3), 1p/19q loss (n = 10), isolated loss 9q (n = 2), and PTEN loss (n = 3), which were not associated with tumor type or location, higher cell proliferation, or distinguishing clinical features (mean age of epilepsy onset, 9 years; age at surgery = 31 years; 69% free from seizure); none had progression on magnetic resonance imaging (mean follow-up, 6 years).