The relationship between the waiting time of postoperative radiotherapy and the prognosis of high grade glioma:a systemic review and meta-analysis.

Objective: The relationship between the waiting time of postoperative radiotherapy and the prognosis of patients with high-grade glioma is still inconclusive, and we addressed this issue through a systematic review and meta-analysis. Methods: Twenty studies published between 1975 and 2019 about waiting times (WT) of radiotherapy with high-grade glioma were retrieved for meta-analysis.The meta-analysis was performed by converting the effect sizes of different WT into regression coefficients ({beta}) and standard error (SE) to indicate the daily impact of delay on OS. Results: A total of 8462 high-grade glioma patients were included in the 20 studies, and no correlation between WT delay and OS was found in the unadjusted model through meta-analysis (HR=1, 95%CI=0.99-1.01, p=0.962). Meta-regression was used to adjust for other prognostic factors and no clear evidence of the relationship between WT delay and OS was found. Conclusion: This meta-analysis suggests that there is no clear evidence for the effect of delayed radiotherapy on OS with high-grade glioma patients.