Should Adjuvant Radiotherapy be Used in Atypical Meningioma (WHO Grade II) Following Gross Total Resection? A Systematic Review and Meta-Analysis

Abstract

The role of adjuvant radiotherapy (RT) following gross total resection (GTR) in atypical meningioma (AM) is not well established. Non-randomized prospective trials, such as RTOG 0539, suggest to treat this group with adjuvant RT. However, it remains unclear if there is any improvement in progression free survival (PFS) and overall survival (OS) with this approach. We aim to evaluate the survival benefit of adjuvant RT in AM following GTR.We performed a systematic review and meta-analysis to aggregate the clinical outcomes of patients with AM who had undergone GTR, treated with and without adjuvant RT. We searched biomedical databases, such as Medline, EMBASE and CENTRAL, for studies published between January 1964 and February 2021. Both prospective and retrospective studies which reported the primary outcomes of 5-year PFS and 5-year OS were included. Extracted data was analyzed using random-effects meta-analysis of time to event using the DerSimonian and Laird methods.Thirteen studies, involving 1124 patients, were included in our meta-analysis. 832 (74.0%) patients were treated with GTR alone and 302 (26.9%) patients had GTR followed by adjuvant RT. Adjuvant RT was delivered as external beam RT (3D conformal RT, intensity modulated RT, fractionated stereotactic radiotherapy) in 10 (76.9%) studies. Three (23.1%) studies also included patients treated with stereotactic radiosurgery in addition to fractionated RT. Median RT dose was 59.4 Gy. Adjuvant RT resulted in an increase of 3.9 months for restricted mean PFS truncated at 60 months (95% confidence interval (CI) 0.23-7.72; P = 0.037) and a non-statistically significant 22% reduction in the hazard of disease progression or death (hazards ratio 0.78; 95% CI 0.46-1.33; P = 0.370). Restricted mean OS, truncated at 60 months, was improved with adjuvant RT by 1.1 months (95% CI 0.37-1.81; P = 0.003) and a non-significant 21% reduction in the hazard of death from any cause (HR 0.79; 95% CI 0.51-1.24; P = 0.310).The use of adjuvant RT in patients with AM who have undergone GTR improved restricted mean PFS and OS. While we await the results from ongoing randomized controlled trials, adjuvant RT should be recommended.C. Wujanto: None. Y. Soon: None. T.Y. Chan: None. B. Vellayappan: None.