Clinical, oncological, and seizure outcomes following surgery for hippocampal gliomas: A systematic review and meta-analysis

Background: Hippocampal gliomas are uncommon tumors located in the temporal lobe, frequently associated with seizures and presenting surgical challenges in proximity to limbic and cognitive regions. The evidence predominantly derives from various retrospective studies, with limited focused analyses on presentation, treatment, and outcomes. Methods: A systematic review and meta-analysis adhered to preferred reporting items for Systematic Reviews and Meta-Analyses guidelines to evaluate outcomes following hippocampal glioma surgery. Studies reporting postoperative results were identified through comprehensive database searches. Pooled proportions for improvement, stability, deterioration, recurrence, mortality, and seizures were estimated using random-effects models. Subgroup analyses examined tumor grade, location, surgical technique, and seizure classification. Bias assessment was conducted utilizing ROBINS-I and Joanna Briggs tools for small case series. Results: Fourteen studies comprising 639 patients were included. Pooled postoperative clinical improvement occurred in 58.7% (95% confidence interval 41.3–76.0) of low-grade and 32.7% (11.9–53.5) of high-grade tumors, while clinical worsening remained uncommon (≤ 4.0% across grades). Mesial temporal tumors demonstrated higher improvement rates than nonmesial tumors (85.0% vs. 68.4%). Favorable seizure outcomes (Engel I–II) were achieved in 77.9% (46.3–109.0), with seizure worsening in < 1%. Recurrence and mortality rates were low overall, with a pooled recurrence of 0.15% and mortality of 0.35% in low-grade tumors, compared with 4.1–7.3% in high-grade tumors, respectively. Conclusion: This meta-analysis reviews outcomes after hippocampal glioma surgery, highlighting common postoperative improvements and seizure control, as well as variability and study limitations. It stresses the need for standardized, prospective research to better understand this rare tumor group.