Design: International, open-label, phase 3 randomised controlled trial
Population: 157 adults after complete resection of WHO grade 2 atypical meningioma
Primary outcome: Disease-free survival
Effect: 5-year DFS 79.9% vs 64.3%; HR 0.51 (95% CI 0.27 to 0.97)

ROAM/EORTC-1308 randomised 157 adults who had complete resection of a newly diagnosed WHO grade 2 atypical meningioma to 60 Gy of adjuvant radiotherapy or MRI observation, at 58 centres in 11 countries. It appeared in The Lancet on 25 September 2026.

At a median of 64 months, recurrence occurred in 14% with radiotherapy and 30% with observation. Five-year disease-free survival was 79.9% versus 64.3% (HR 0.51, 95% CI 0.27 to 0.97). Grade 2 or 3 radiation-related serious adverse events affected 8%, with no treatment-related deaths.

This tips a long-running uncertainty towards offering radiotherapy, but the trial was small and the confidence interval wide. The trade-off between fewer recurrences and possible late effects of brain radiotherapy is a decision to make with the patient.

After complete resection of atypical meningioma, adjuvant radiotherapy is worth discussing with every patient
Expect fewer recurrences: about 14% versus 30% over five years in this trial
Discuss possible late effects of brain radiotherapy as part of the decision
Observation with MRI remains a reasonable choice for patients who weigh late effects more heavily

Why it matters

It answers a question neurosurgeons and oncologists have argued over for years with randomised data.

The statistics, in plain English

The upper end of the hazard ratio interval (0.97) sits close to 1, so the true benefit could be much smaller than the halving seen. The absolute difference interval (0.6 to 30.5 points) is similarly wide, reflecting only 157 patients.