Dendritic Cell Vaccines for Glioblastoma: A Systematic Review and Meta-AnalysisComparing New-Onset and Recurrent Cases

Introduction: Glioblastoma (GBM), an aggressive and highly recurrent brain tumor, remains a significant challenge despite advancements in treatment. With a median survival of only 15 months and recurrence often occurring within a year despite aggressive initial therapy, there is an urgent need for more effective therapeutic strategies. The interplay of intrinsic and extrinsic factors, such as genetic mutations and alterations in the tumor microenvironment, drives recurrence, highlighting the importance of targeted approaches. Emerging therapies, particularly dendritic cell (DC)-based immunotherapies, show promise in enhancing anti-tumor immune responses. This study aimed to compare the effectiveness of DC-based immunotherapy in improving survival outcomes for patients with newly diagnosed or recurrent GBM. Methods: We conducted a comprehensive search across four electronic databases (Cochrane Central Register of Controlled Trials, PubMed, Scopus, and Web of Science) up to March 2024 to identify pertinent studies evaluating the efficacy of DC vaccines in the treatment of both newly diagnosed and recurrent GBM. The quality of evidence from trials was assessed using the Cochrane risk-of-bias version 1 (RoB1) tool. Data from the included studies were extracted into a standardized online sheet and analyzed using Review Manager (RevMan) 5.4. Results: Our search identified three records with a total of 355 patients. The results of the meta-analysis showed that DC-based immunotherapy had a greater impact on recurrent GBM than on newly diagnosed GBM. However, overall survival favored newly diagnosed cases, demonstrating a more protective effect (HR = 0.62, 95% confidence intervals (CI) (0.46,0.84), p = 0.002) with no significant heterogeneity (p = 0.97, I2 = 0%). A similar trend was observed for progression-free survival, favoring newly diagnosed cases over recurrent ones (HR = 0.56, 95% CI (0.31,1.00), p = 0.05), with no significant heterogeneity (p = 0.48, I2 = 0%). Moreover, comparable results were observed for survival at both 12 and 24 months Conclusion: Dendritic cell-based immunotherapy can enhance survival outcomes in GBM patients. The results showed DC-based immunotherapy to be more effective in newly diagnosed GBM than in recurrent cases.