Background: Glioblastoma remains the most aggressive and treatment-resistant primary brain tumor, with patient outcomes strongly associated with the extent of surgical resection. Tumor recurrence is largely driven by infiltrating glioma cells that extend beyond the contrast-enhancing margin, which has traditionally served as the boundary for surgical resection. Advances in pre- and intraoperative imaging, functional mapping, and fluorescence guidance have challenged the conventional definition of “maximal safe resection” and given rise to the concept of supramaximal resection (SMR). This technique, where surgical resection extends beyond the contrast-enhancing border, has garnered significant interest in recent years and shown promising preliminary survival outcomes. However, the lack of standardized definitions and methodological consistency has limited reproducibility and clinical adoption. Methods: A systematic literature search of PubMed/MEDLINE, Embase, and Web of Science was performed from database inception through March 2026 in accordance with PRISMA guidelines. Studies investigating resection beyond the contrast-enhancing tumor margin in adult glioblastoma patients were evaluated for inclusion. Results: A total of 1045 records were identified, with 37 studies meeting inclusion criteria. Across studies, SMR was frequently associated with improved progression-free and overall survival in selected patients, particularly following complete contrast-enhancing tumor resection. However, substantial heterogeneity exists in SMR definitions, and the current body of evidence is largely retrospective and derived from high-volume centers. Conclusions: SMR represents a promising extension of maximal safe resection targeting infiltrative tumor beyond conventional imaging boundaries. While emerging evidence suggests survival benefits, variability in methodology and patient-specific factors require cautious interpretation. Future standardization and prospective validation are needed to better define the role of SMR within multimodal glioblastoma treatment.

BACKGROUND AND OBJECTIVES: Glioblastoma often extends along the subventricular zone and resection frequently results in ventricular entry, which is associated with increased risk of postoperative hydrocephalus. Choroid plexus cauterization (CPC) is a treatment for pediatric hydrocephalus, but its utility in preventing postoperative hydrocephalus following glioblastoma resection with ventricular entry is unknown. We sought to characterize CPC safety and efficacy in preventing postoperative hydrocephalus in this setting. METHODS: We evaluated a historical cohort of 260 patients who underwent craniotomy for glioblastoma with ventricular entry, assessing postoperative hydrocephalus, survival, and functional outcomes. Furthermore, we prospectively performed CPC in a matched cohort with ventricular entry. We quantitated the volume of choroid plexus that was successfully cauterized using magnetic resonance segmentation and evaluated the safety and efficacy of CPC. RESULTS: 25.8% of patients with glioblastoma resection with ventricular entry developed postoperative hydrocephalus. Hydrocephalus was associated with more readmissions (2.3 vs 0.6; P < .0001), longer hospital stays (10.0 vs 6.5 days; P = .0047), and lower 3-month Karnofsky Performance Status (64.4 vs 78.6; P < .0001), although overall survival was unaffected. Thirty patients underwent prospective CPC with no procedure-related postoperative complications. Choroid plexus volume in the involved ventricle decreased by 50% on postoperative MRI segmentations ( P = .0020). In a matched analysis, there was a reduction in postoperative hydrocephalus compared with the retrospective cohort (3.3% vs 25.8%; P = .0060) associated with fewer hospital readmissions ( P = .0330). CONCLUSION: As ventricular entry becomes increasingly common during supramaximal glioblastoma resection, our data demonstrate that patients who develop postoperative hydrocephalus have more readmissions, longer hospital stays, and worse functional status. Thus, strategies to reduce postoperative hydrocephalus are critical. Although it does not alter the natural course of glioblastoma itself, we find that CPC represents a safe and effective adjunct that prevents postoperative hydrocephalus, reduces hospital readmissions, and downstream interventions, which is extremely important to a patient cohort with limited expected survival.