Introduction: Infiltrated peritumoral neocortex appears to be a key structure for glioma-related epileptogenesis that may explain both the anti-epileptic effects of oncological treatments and the increase in seizure frequency as tumors progress.
Methods: 182 consecutive patients aged 18–70 years were randomly assigned to either the trial group (iMRI group) or conventional neuronavigation. Patients with less than 6 months of postoperative follow-up and neuropathologically confirmed nonglioma lesions were excluded. Benign histologies were excluded from the secondary end-point follow-up. The patients were screened for the presence of at least one de novo epileptic seizure at presentation, resulting in subgroups of patients with and without epilepsy. The cases were analyzed for short and long-term neurological outcome, progression-free survival (PFS), overall survival (OS), seizure freedom and extent of resection (EOR). Wilcoxon non-parametric test or Fisher exact test was applied for continuous or categorical variables.
Results: 59(59.6%) and 26 (33.3%) patients presented with seizures in the LGG and HGG group (p=0.001). No patient had intractable epilepsy and a pre-operative seizure duration of more than 6 months was present in 27% and 13% for LGG and respectively HGG groups (p=0.108). Of the 177 patients included for survival analysis, 78(44%) had a LGG and 99(56%) had a HGG. In the LGG group, the age (0.034) and gender (0.042) were the only significant variable differing between the patients with or without pre-operative seizure. Pre-operative tumor volume was significantly different in the patients with or without seizures in the HGG group (p=0008). In the LGG group, log-rank test demonstrated a statistically significant OS (p=0.0044) and PFS (p=0.0172) benefit in the patients without seizure after surgery. An OS (p=0.4743) and PFS (p=0.5773) benefit trend was noted in the group of patients with HGG.
Conclusions: Persistent or new post-operative seizures might indicate tumor recurrence/progression and thus serve as a prognostic marker for survival.
Patient Care: This study emphasizes the need of an extensive knowledge of the natural history and anatomical peculiarities of each tumor to achieve state of the art surgery and to improve the available treatments available to patients. The peritumoral neocortex seems to represent a pivotal structure both for the genesis of epileptic activity and for infiltration by glioma cells, which has significant implications in terms of the treatment recommended to the patients and their oncological prognosis.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) discuss the benefit of further assessment of tumor related seizure
2) outline the importance of good seizure control
3) recognize the need of a thorough follow-up of the seizure-related symptoms