Background
Phase 3, open-label, multicentre randomized trial (58 sites, 11 countries). N=157 adults (≥16 y) with newly diagnosed WHO grade 2 atypical meningioma after surgeon-assessed complete resection. Question: does adjuvant RT reduce recurrence vs observation (active surveillance)?
Results
Interventions and follow up: Arm A: Adjuvant IMRT 60 Gy/30 fractions over 6 wk (n=78)
Arm B: Observation with MRI surveillance (n=79)
Primary endpoint: DFS (MRI-confirmed recurrence or death from any cause), ITT
mFollow up: 64 months (IQR 50–75); minimum 4 y
Results: DFS: HR 0.51 (95% CI 0.27–0.97), P=.0396
5-y DFS: 79.9% (95% CI 67.6–87.9) vs 64.3% (95% CI 51.9–74.2); absolute difference 15.6 pts (95% CI 0.6–30.5)
Recurrence: 14% (11/78) vs 30% (24/79)
OS: NR
Arm B: Observation with MRI surveillance (n=79)
Primary endpoint: DFS (MRI-confirmed recurrence or death from any cause), ITT
mFollow up: 64 months (IQR 50–75); minimum 4 y
Results: DFS: HR 0.51 (95% CI 0.27–0.97), P=.0396
5-y DFS: 79.9% (95% CI 67.6–87.9) vs 64.3% (95% CI 51.9–74.2); absolute difference 15.6 pts (95% CI 0.6–30.5)
Recurrence: 14% (11/78) vs 30% (24/79)
OS: NR
Adverse events
Grade 2–3 radiation-related SAEs: 5/66 (8%) with RT (as-treated)
Treatment-related deaths: 0
Other AE detail: NR in abstract
Treatment-related deaths: 0
Other AE detail: NR in abstract
Conclusions
Adjuvant RT after complete resection of atypical meningioma reduced recurrence and improved DFS vs observation. RT should be considered when recurrence prevention is valued over potential late RT toxicity, with individualized shared decision-making.
Key Limitations
Open-label design; small trial (n=157) with wide CIs, P=.0396 and lower CI bound of the absolute 5-y difference just above 0. Primary endpoint DFS (MRI recurrence) rather than OS; no OS benefit reported. Follow-up may be too short to capture late RT neurocognitive and vascular toxicity. Completeness of resection was surgeon-assessed. Recruitment of 157 patients over 5 y from 990 assessed suggests selected population.
Clinical Context
First randomized phase 3 evidence on adjuvant RT for completely resected grade 2 meningioma; prior practice relied on retrospective series and observation was common (NRG/RTOG 0539 was single-arm). Contrasts with ROAM/EORTC-1308 as a direct test of the observation strategy, and may shift guideline positioning toward considering adjuvant RT after gross total resection. Molecular/methylation risk stratification not yet used to select patients.