Rinse and Repeat? The Role of Reirradiation in Meningiomas – A Systematic Review and Meta-Analysis

Introduction Meningiomas are the most common primary brain tumors in adults. Surgery and radiation therapy are the main treatment options and often achieve initial tumor control. However, tumor progression and local recurrence represent significant challenges, particularly in WHO grade 2 and 3 meningiomas. Reirradiation is a potential treatment option in such cases, but its outcomes are poorly defined. This systematic review and meta-analysis evaluates the role of reirradiation in meningiomas. Materials and Methods The review and analyses follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results In total, 1350 publications were screened, and 16 studies with 385 patients were included. The overall median interval between initial radiation therapy and reirradiation was 38 months. Patients were reirradiated with stereotactic techniques or fractionated radiation therapy, including a notable number of patients receiving particle therapy. The local control rate after reirradiation was 53% (95% confidence interval (CI): 48 – 58%, I 2 =17.20%, p=0.30). The overall survival rate was 73% (95% CI: 67 – 78%, I 2 =23.41%, p=0.27). The rate of symptomatic radiation necrosis was 8% (95% CI: 5 – 11%, I 2 =6.29%, p=0.38). Rates of other acute and chronic adverse events of any grade were 22% (95% CI: 17 – 28%, I 2 =38.20%, p=0.20) and 16% (95% CI: 11 – 21%, I 2 =78.41%, p=0.01). High-grade toxicity was rare. There was considerable heterogeneity in reporting and a notable risk of bias across all studies. Conclusions Based on the available evidence, reirradiation may represent a safe and effective treatment for recurrent meningiomas. Due to the small number of studies, limited follow-up, cohort and treatment heterogeneity, risk of bias, and the lack of standardized reporting, further research, ideally in the setting of prospective trials, is critical to defining the role of reirradiation.