Immunotherapeutic Intervention for Glioblastoma Multiforme: A Systematic Literature Review and Meta-Analysis Discussing Outcomes and Future Directions

Introduction: Current standard of care (SOC) treatment for Glioblastoma multiforme (GBM) involves aggressive surgical resection, temozolomide (TMZ) chemotherapy, and radiation. Advancements in immunotherapy (IT) for other cancer types have drawn attention to the potential use of IT for GBM. We aim to synthesize evidence regarding current IT treatments for GBM, assess therapeutic outcomes, and discuss future perspectives.

Methods: A systematic review of the literature using PubMed, Google Scholar, and Web of Science electronic databases was completed according to the PRISMA guidelines. We identified articles discussing immunotherapeutic management of GBM.

Results: 30 studies including 979 patients were analyzed. The mean age was 52.3 ± 4.54 years, and 53% of patients were male. Patients treated with IT were associated with a significantly longer overall survival (OS) (SMD: 0.82, CI: 0.13-1.5, p< 0.001) compared to patients treated with SOC only. Eighteen case studies with a total of 95 patients undergoing IT treatment were then analyzed. The mean age was 52.6 ± 16.9 years, and 61% were male. Gross total tumor resection (GTR), when compared to subtotal resection (STR), was associated with significantly longer progression-free survival (PFS) (21.3 months vs. 9.21 months, p< 0.05) and OS (29.0 months vs. 16.6 months, p< 0.05). Methylated 06-methylguanine-DNA methyltransferase (MGMT) promoter, when compared to un-methylated MGMT, had a significantly longer PFS (22.8 months vs. 12.0 months, p< 0.05) but not a longer OS (p=0.06). For patients whose treatment included concurrent steroids with IT, odds-ratio (OR) analysis for OS length revealed a significantly lower OR (0.89, CI: 0.82-0.96, p< 0.005).

Conclusion : Immunotherapeutic treatment appears to have potential in improving survival outcomes in patients with GBM. Additionally, it is important to consider tumor genetic components, concurrent medication management, and degree of surgical intervention when evaluating treatment plans and patient prognosis.