Seizure outcome in temporal glioblastoma surgery: lobectomy as a supratotal resection regime outclasses conventional gross-total resection

Status epilepticus in patients with glioblastoma: Clinical characteristics, risk factors, and epileptological outcome

PURPOSE

Epilepsy is a common comorbidity in patients with glioblastoma, however, clinical data on status epilepticus (SE) in these patients is sparse. We aimed to investigate the risk factors associated with the occurrence and adverse outcomes of SE in glioblastoma patients.

METHODS

We retrospectively analysed electronic medical records of patients with de-novo glioblastoma treated at our institution between 01/2006 and 01/2020 and collected data on patient, tumour, and SE characteristics.

RESULTS

In the final cohort, 292/520 (56.2 %) patients developed seizures, with 48 (9.4 % of the entire cohort and 16.4 % of patients with epilepsy, PWE) experiencing SE at some point during the course of their disease. SE was the first symptom of the tumour in 6 cases (1.2 %) and the first manifestation of epilepsy in 18 PWE (6.2 %). Most SE episodes occurred postoperatively (n = 37, 77.1 %). SE occurrence in PWE was associated with postoperative seizures and drug-resistant epilepsy. Adverse outcome (in-house mortality or admission to palliative care, 10/48 patients, 20.8 %), was independently associated with higher status epilepticus severity score (STESS) and Charlson Comorbidity Index (CCI), but not tumour progression. 32/48 SE patients (66.7 %) were successfully treated with first- and second-line agents, while escalation to third-line agents was successful in 6 (12.5 %) cases.

CONCLUSION

Our data suggests a link between the occurrence of SE, postoperative seizures, and drug-resistant epilepsy. Despite the dismal oncological prognosis, SE was successfully treated in 79.2 % of the cases. Higher STESS and CCI were associated with adverse SE outcomes.

Lobectomy versus gross total resection for glioblastoma multiforme: A systematic review and individual-participant data meta-analysis

Overall survival (OS)for glioblastoma multiforme (GBM) has a known association with the extent of tumor resection with gross total resection (GTR) typically considered as the upper limit. In certain regions such as the anterior temporal lobe, more extensive resection by means of a lobectomy may be feasible. In our systematic review and meta-analysis, we aimed to compare the outcomes of lobectomy and GTR for GBM. PubMed and Embase were queriedfor studies that compared the outcomes after lobectomy or GTR for GBM. The primary outcomes were OS, progression-free survival (PFS), and Karnofksy Performance Status (KPS) score at the latest follow-up. The secondary outcomes were seizure control at the latest follow-up and complication rates. Meta-analysis for OS and PFS was performed using individual-participant data reconstructed from published Kaplan-Meier curves. Random-effect meta-analysis was performed for KPS. The secondary outcomes were pooled using descriptive statistics. Of the 795 records screened, 6 were included in our study. Meta-analysis revealed that anterior temporal, frontal, or occipital lobectomy was associated with significantly better OS (p < 0.001) and PFS (p < 0.001) than GTR, but not KPS (MD = 6.37; 95% CI=(-13.80, 26.54); p = 0.536). Anterior temporal lobectomy was associated with significantly better seizure control rates than GTR for temporal GBM (OR = 27; 95% CI=(1.4, 515.9); p = 0.002). There was no statistically significant difference in complication rates between anterior temporal, frontal, or occipital lobectomy and GTR. In conclusion, lobectomy was associated with significantly better OS, PFS, and seizure control than GTR for GBM.

A Systematic Review and Meta-Analysis of Supramarginal Resection versus Gross Total Resection in Glioblastoma: Can We Enhance Progression-Free Survival Time and Preserve Postoperative Safety?

To date, gross total resection (GTR) of the contrast-enhancing area of glioblastoma (GB) is the benchmark treatment regarding surgical therapy. However, GB infiltrates beyond those margins, and most tumors recur in close proximity to the initial resection margin. It is unclear whether a supramarginal resection (SMR) enhances progression-free survival (PFS) time without increasing the incidence of postoperative surgical complications. The aim of the present meta-analysis was to investigate SMR with regard to PFS and postoperative surgical complications. We searched for eligible studies comparing SMR techniques with conventional GTR in PubMed, Cochrane Library, Web of Science, and Medline databases. From 3158 initially identified records, 11 articles met the criteria and were included in our meta-analysis. Our results illustrate significantly prolonged PFS time in SMR compared with GTR (HR: 11.16; 95% CI: 3.07–40.52, p = 0.0002). The median PFS of the SMR arm was 8.44 months (95% CI: 5.18–11.70, p < 0.00001) longer than the GTR arm. The rate of postoperative surgical complications (meningitis, intracranial hemorrhage, and CSF leaks) did not differ between the SMR group and the GTR group. SMR resulted in longer median progression-free survival without a negative postoperative surgical risk profile. Multicentric prospective randomized trials with a standardized definition of SMR and analysis of neurologic functioning and health-related quality of life are justified and needed to improve the level of evidence.

Oncological and functional neurosurgery: Perspectives for the decade regarding diffuse gliomas

For decades, diffuse glioma (DG) studies mostly focused on oncological considerations, whereas functional outcomes received less attention. Currently, because overall survival has increased in DG, especially in low-grade glioma (overall survival > 15 years), quality of life including neurocognitive and behavioral aspects should be assessed and preserved more systematically, particularly regarding surgery. Indeed, early maximal tumor removal results in greater survival in both high-grade and low-grade gliomas, leading to propose "supra-marginal" resection, with excision of the peritumoral zone in diffuse neoplasms. To minimize functional risks while maximizing the extent of resection, traditional "tumor-mass resection" is replaced by "connectome-guided resection" conducted under awake mapping, taking into account inter-individual brain anatomo-functional variability. A better understanding of the dynamic interplay between DG progression and reactional neuroplastic mechanisms is critical to adapt a personalized multistage therapeutic strategy, with integration of functional neurooncological (re)operation(s) in a multimodal management scheme including repeated medical therapies. Because the therapeutic armamentarium remains limited, the aims of this paradigmatic shift are to predict one/several step(s) ahead glioma behavior, its modifications, and compensatory neural networks reconfiguration over time in order to optimize the onco-functional benefit of each treatment - either in isolation or in combination with others - in human beings bearing a chronic tumoral disease while enjoying an active familial and socio-professional life as close as possible to their expectations. Thus, new ecological endpoints such as return to work should be incorporated into future DG trials. "Preventive neurooncology" might also be envisioned, by proposing a screening policy to discover and treat incidental glioma earlier.

Molecular pathology and clinical implications of diffuse glioma

ABSTRACT

The prognosis for diffusely infiltrating gliomas at World Health Organization (WHO) grade 2-4 remains dismal due to their heterogeneity. The rapid development of genome-wide molecular-profiling-associated studies has greatly promoted the accuracy of glioma classification. Thus, the latest version of the WHO classification of the central nervous system tumors published in 2021 has incorporated more molecular biomarkers together with histological features for the diagnosis of gliomas. Advanced usage of molecular pathology in clinical diagnostic practice provides also new opportunities for the therapy of patients with glioma, including surgery, radiotherapy and chemotherapy, targeted therapy, immunotherapy, and more precision clinical trials. Herein, we highlight the updates in the classification of gliomas according to the latest WHO guidelines and summarize the clinically relevant molecular markers by focusing on their applications in clinical practice. We also review the advances in molecular features of gliomas, which can facilitate the development of glioma therapies, thereby discussing the challenges and future directions of molecular pathology toward precision medicine for patients with glioma.

Management of epilepsy in brain tumor patients

PURPOSE OF REVIEW

A concise review of recent findings in brain tumor-related epilepsy (BTRE), with focus on the effect of antitumor treatment on seizure control and the management of antiepileptic drugs (AEDs).

RECENT FINDINGS

Isocitrate dehydrogenase mutation and its active metabolite d -2-hydroxyglutarate seem important contributing factors to epileptogenesis in BTRE. A beneficial effect of antitumor treatment (i.e. surgery, radiotherapy, and chemotherapy) on seizure control has mainly been demonstrated in low-grade glioma. AED prophylaxis in seizure-naïve BTRE patients is not recommended, but AED treatment should be initiated after a first seizure has occurred. Comparative efficacy randomized controlled trials (RCTs) are currently lacking, but second-generation AED levetiracetam seems the preferred choice in BTRE. Levetiracetam lacks significant drug-drug interactions, has shown favorable efficacy compared to valproic acid in BTRE, generally causes no hematological or neurocognitive functioning adverse effects, but caution should be exercised with regard to psychiatric adverse effects. Potential add-on AEDs in case of uncontrolled seizures include lacosamide, perampanel, and valproic acid. Ultimately, in the end-of-life phase when oral intake of medication is hampered, benzodiazepines via nonoral administration routes are potential alternatives.

SUMMARY

Management of seizures in BTRE is complex and with currently available evidence levetiracetam seems the preferred choice. Comparative efficacy RCTs in BTRE are warranted.

Clinical and prognostic implications of rim restriction following glioma surgery

Rim restriction surrounding the resection cavity of glioma is often seen on immediate post-op diffusion-weighted imaging (DWI). The etiology and clinical impact of rim restriction are unknown. We evaluated the incidence, risk factors and clinical consequences of this finding. We evaluated patients that underwent surgery for low-grade glioma (LGG) and glioblastoma (GBM) without stroke on post-operative imaging. Analyses encompassed pre- and postoperative clinical, radiological, intraoperative monitoring, survival, functional and neurocognitive outcomes. Between 2013 and 2017, 63 LGG and 209 GBM patients (272 in total) underwent surgical resection and were included in our cohort. Post-op rim restriction was demonstrated in 68 patients, 32% (n = 20) of LGG and 23% (n = 48) of GBM patients. Risk factors for restriction included temporal tumors in GBM (p = 0.025) and insular tumors in LGG (p = 0.09), including longer surgery duration in LGG (p = 0.008). After a 1-year follow-up, LGG patients operated on their dominant with post-op restriction had a higher rate of speech deficits (46 vs 9%, p = 0.004). Rim restriction on postoperative imaging is associated with longer duration of glioma surgery and potentially linked to brain retraction. It apparently has no direct clinical consequences, but is linked to higher rates of speech deficits in LGG dominant-side surgeries.

Temporal lobe epilepsy surgery: Piriform cortex resection impacts seizure control in the long-term

Objective

Recently, we showed that resection of at least 27% of the temporal part of piriform cortex (PiC) strongly correlated with seizure freedom 1 year following selective amygdalo‐hippocampectomy (tsSAHE) in patients with mesial temporal lobe epilepsy (mTLE). However, the impact of PiC resection on long‐term seizure outcome following tsSAHE is currently unknown. The aim of this study was to evaluate the impact of PiC resection on long‐term seizure outcome in patients with mTLE treated with tsSAHE.

Methods

Between 2012 and 2017, 64 patients were included in the retrospective analysis. Long‐term follow‐up (FU) was defined as at least 2 years postoperatively. Seizure outcome was assessed according to the International League against Epilepsy (ILAE). The resected proportions of hippocampus, amygdala, and PiC were volumetrically assessed.

Results

The mean FU duration was 3.75 ± 1.61 years. Patients with ILAE class 1 revealed a significantly larger median proportion of resected PiC compared to patients with ILAE class 2–6 [46% (IQR 31–57) vs. 16% (IQR 6–38), p = 0.001]. Resected proportions of hippocampus and amygdala did not significantly differ for these groups. Among those patients with at least 27% resected proportion of PiC, there were significantly more patients with seizure freedom compared to the patients with <27% resected proportion of PiC (83% vs. 39%, p = 0.0007).

Conclusions

Our results show a strong impact of the extent of PiC resection on long‐term seizure outcome following tsSAHE in mTLE. The authors suggest the PiC to constitute a key target volume in tsSAHE to achieve seizure freedom in the long term.

Converging Mechanisms of Epileptogenesis and Their Insight in Glioblastoma

Glioblastoma (GBM) is the most common and advanced form of primary malignant tumor occurring in the adult central nervous system, and it is frequently associated with epilepsy, a debilitating comorbidity. Seizures are observed both pre- and post-surgical resection, indicating that several pathophysiological mechanisms are shared but also prompting questions about how the process of epileptogenesis evolves throughout GBM progression. Molecular mutations commonly seen in primary GBM, i.e., in PTEN and p53, and their associated downstream effects are known to influence seizure likelihood. Similarly, various intratumoral mechanisms, such as GBM-induced blood-brain barrier breakdown and glioma-immune cell interactions within the tumor microenvironment are also cited as contributing to network hyperexcitability. Substantial alterations to peri-tumoral glutamate and chloride transporter expressions, as well as widespread dysregulation of GABAergic signaling are known to confer increased epileptogenicity and excitotoxicity. The abnormal characteristics of GBM alter neuronal network function to result in metabolically vulnerable and hyperexcitable peri-tumoral tissue, properties the tumor then exploits to favor its own growth even post-resection. It is evident that there is a complex, dynamic interplay between GBM and epilepsy that promotes the progression of both pathologies. This interaction is only more complicated by the concomitant presence of spreading depolarization (SD). The spontaneous, high-frequency nature of GBM-associated epileptiform activity and SD-associated direct current (DC) shifts require technologies capable of recording brain signals over a wide bandwidth, presenting major challenges for comprehensive electrophysiological investigations. This review will initially provide a detailed examination of the underlying mechanisms that promote network hyperexcitability in GBM. We will then discuss how an investigation of these pathologies from a network level, and utilization of novel electrophysiological tools, will yield a more-effective, clinically-relevant understanding of GBM-related epileptogenesis. Further to this, we will evaluate the clinical relevance of current preclinical research and consider how future therapeutic advancements may impact the bidirectional relationship between GBM, SDs, and seizures.

Supramarginal Resection for Glioblastoma: It Is Time to Set Boundaries! A Critical Review on a Hot Topic

Glioblastoma are the most common primary malignant brain tumors with a highly infiltrative behavior. The extent of resection of the enhancing component has been shown to be correlated to survival. Recently, it has been proposed to move the resection beyond the contrast-enhanced portion into the MR hyper intense tissue which typically surrounds the tumor, the so-called supra marginal resection (SMR). Though it should be associated with better overall survival (OS), a potential harmful resection must be avoided in order not to create new neurological deficits. Through this work, we aimed to perform a critical review of SMR in patients with Glioblastoma. A Medline database search and a pooled meta-analysis of HRs were conducted; 19 articles were included. Meta-analysis revealed a pooled OS HR of 0.64 (p = 0.052). SMR is generally considered as the resection of any T1w gadolinium-enhanced tumor exceeding FLAIR volume, but no consensus exists about the amount of volume that must be resected to have an OS gain. Equally, the role and the weight of several pre-operative features (tumor volume, location, eloquence, etc.), the intraoperative methods to extend resection, and the post-operative deficits, need to be considered more deeply in future studies.