Adjuvant radiotherapy versus observation following gross total resection for atypical meningioma: a systematic review and meta-analysis

Abstract

Background The impact of adjuvant radiotherapy (RT) on atypical meningioma (AM) underwent a gross total resection (GTR) remains unclear, showing conflicting results from various studies. The objective of this study was to perform an updated meta-analysis for observational studies to determine the effect of adjuvant RT after GTR on local recurrence and survival outcomes compared to observation after GTR. Methods PubMed, Embase, and Web of Science were searched to identify comparative studies that reported outcomes of adjuvant RT versus observation for AM patients after GTR. Local recurrence rate, progression-free survival (PFS), overall survival (OS), and toxicities related to RT were considered as outcomes of interest. Differences between two cohorts were estimated by calculating odds ratios (OR) for LR rate and hazard ratios (HR) for survival outcomes with 95% confidence intervals (CIs) for meta-analysis, using R version 4.0.3 software. Included studies were appraised with the Risk of Bias Assessment tool for Non-Randomized Studies. Outcome ratios were combined with the Mantel–Haenszel method and the inverse variance-weighted method, appropriately. Results Data from 30 studies involving 2904 patients (adjuvant RT: n = 737; observation: n = 2167) were eventually included. Significant reduction of local recurrence rate was seen in the adjuvant RT cohort compare to that in the observation cohort (OR 0.50; 95% CI 0.36–0.68; p < 0.0001). Pooled HRs of PFS at 1-year, 3-year, 5-year, and > 5-year revealed that adjuvant RT was superior to observation. There was no significant difference in OS between the two cohorts during any period. Most toxicities were tolerable with grade 1 or 2. There was no documented grade 5 toxicity. Conclusions For AM patients who underwent GTR, evidence suggested that adjuvant RT could potentially decrease local recurrence and improve PFS better than observation.

Radiotherapy for meningiomas

“…Song et al [ 33 ] accumulated 24 studies reporting on 3078 patients with WHO grade 2 meningioma, finding that post-operative radiotherapy improved progression free survival regardless of resection extent with a pooled hazard ratio of 0.41 (95% confidence interval 0.30–0.55) after subtotal resection, and 0.73 (95% confidence interval 0.52–0.92) after gross total resection. Similarly, Chun et al [ 34 ] identified 25 studies reporting outcomes of WHO grade 2 meningiomas following gross total resection, comprised of 1232 patients not receiving postoperative radiotherapy and 384 patients receiving postoperative radiation. Again, postoperative radiotherapy improved local recurrence and progression free survival, with pooled hazard ratios of 0.50 (95% confidence interval 0.36–0.68) and 0.66 (95% confidence interval 0.51–0.84), respectively.…”

Long-Term Follow-Up, Treatment Strategies, Functional Outcome, and Health-Related Quality of Life after Surgery for WHO Grade 2 and 3 Intracranial Meningiomas

“…In contrast, patients in our cohort did not receive routine RT after surgery for a grade 2 or 3 meningioma. Time to recurrence was shorter and tumor control worse in our patients than in patients who received RT after surgery in the published literature [ 38 , 39 ]. However, long-term follow-ups typically show that meningiomas recur despite RT, indicating that the benefit is the delay of recurrence rather than the cure.…”

“…SRS is typically recommended for small residual or recurrent tumors [ 24 ]. Several studies have shown that RT improves PFS but not OS [ 38 , 39 ]. Rogers et al [ 12 ] reported a 59% 3-year PFS and 69% local control after RT for high-risk meningiomas, indicating that RT may be beneficial in these patients.…”

Adjuvant Radiotherapy Versus Surveillance for Grade 2 Intracranial Meningiomas: A Multi-Institutional Propensity Score-Matched Study

“…This may be secondary to the heterogeneity in the indications for ART across institutions and selection bias, given that our ART group exhibited more unfavorable characteristics such as a larger tumor size, lesser GTR, and higher Ki-67. However, a recent meta-analysis of retrospective studies observed that ART significantly increases PFS after GTR of atypical meningiomas (30). Table 3 shows the results of retrospective series comparing ART and surveillance and the results of prospective non-randomized studies.…”