A landmark phase III randomized controlled trial published in The Lancet on September 25, 2026, has demonstrated that adjuvan radiotherapy significantly improves disease-free survival following complete surgical resection of WHO grade 2 meningioma, addressing a longstanding controversy in neuro-oncology.
The international ROAM/EORTC-1308 trial, led by Michael D. Jenkinson and colleagues, found that postoperative radiotherapy reduced the hazard of recurrence or death by approximately 49% compared with observation alone.
The findings provide the first randomized evidence supporting adjuvant radiotherapy in this setting and could influence future international treatment recommendations.
ROAM/EORTC-1308 Trial Design and Patient Population
The ROAM/EORTC-1308 study was an international, multicenter, open-label phase III randomized controlled trial conducted across 58 hospitals and academic centers in 11 countries.
Between April 2016 and May 2021, investigators screened 990 patients, of whom 157 patients with newly diagnosed WHO grade 2 atypical meningioma were randomized following surgeon-assessed gross total resection (Simpson grades I–III).
Patients were assigned to:
- Adjuvant radiotherapy: 78 patients, allocated to intensity-modulated radiotherapy (IMRT), 60 Gy in 30 fractions over six weeks.
- Observation: 79 patients, followed with scheduled clinical evaluations and MRI surveillance.
Radiotherapy was initiated within 12 weeks after surgery, with a prospective quality-assurance program to ensure consistency in treatment planning and delivery.
The primary endpoint was disease-free survival, defined as time from surgery to MRI-confirmed meningioma recurrence or death from any cause.
Secondary endpoints included overall survival, health-related quality of life, neurocognitive function, time to second-line treatment, and treatment-related toxicity.
Adjuvant Radiotherapy Significantly Improves Disease-Free Survival
After a median follow-up of 64 months, adjuvant radiotherapy demonstrated a statistically significant improvement in disease-free survival compared with observation.
Meningioma recurrence occurred in:
- 14% (11/78) of patients assigned to radiotherapy.
- 30% (24/79) of patients assigned to observation.
The estimated five-year disease-free survival rates were:
- 79.9% with adjuvant radiotherapy.
- 64.3% with observation.
This represented an absolute improvement of 15.6 percentage points (95% CI, 0.6–30.5).
The hazard ratio for recurrence or death was 0.51 (95% CI, 0.27–0.97; P=0.0396), corresponding to an approximately 49% relative reduction in the hazard of disease recurrence or death.
The findings demonstrate that postoperative radiotherapy can provide clinically meaningful disease control even after apparently complete surgical removal of atypical meningioma.
However, no significant overall survival difference was identified between treatment groups at five years.
Treatment-Related Toxicity and Neurocognitive Outcomes
The survival benefit was accompanied by a generally manageable toxicity profile.
Among the 66 patients who actually received radiotherapy, early radiation-related adverse reactions occurred in approximately 45%, predominantly grade 1–2 events, including scalp erythema, alopecia, fatigue, and headache.
Late radiation-related adverse reactions were reported in 26%, most commonly persistent hair loss, headache, and fatigue.
Radiation-related serious adverse events occurred in five patients (8%), including early headache or seizure and late seizure events or radiation-induced optic neuritis.
One early grade 3 seizure was reported, while no treatment-related deaths occurred.
Importantly, the investigators observed no clear differences in health-related quality of life or neurocognitive function between the radiotherapy and observation groups.
Nevertheless, these findings should be interpreted cautiously because the number of patients completing long-term quality-of-life and neurocognitive assessments decreased substantially over time.
Additional follow-up will be necessary to determine whether late neurological, cognitive, or endocrine complications emerge beyond the currently reported period.
Molecular Analysis Supports the Radiotherapy Benefit
n exploratory molecular analysis was performed in 132 patients (84% of the trial population) using DNA methylation classification and integrated molecular risk scoring.
These analyses investigated whether the benefit of adjuvant radiotherapy remained evident after accounting for differences in underlying tumor biology.
After adjustment for DNA methylation class, radiotherapy continued to demonstrate improved disease-free survival:
HR 0.49 (95% CI, 0.25–0.95; P=0.0358).
Similarly, adjustment for integrated molecular risk score yielded:
HR 0.46 (95% CI, 0.23–0.88; P=0.0203).
These findings suggest that the overall radiotherapy benefit was not explained by differences in molecular risk distribution between treatment groups.
However, the molecular analyses were exploratory and conducted after the original trial design. They do not establish which individual molecular subgroups derive the greatest benefit from adjuvant treatment.
What Do These Findings Mean for Clinical Practice?
The ROAM/EORTC-1308 trial addresses one of the most debated questions in meningioma management: whether patients with completely resected WHO grade 2 tumors should receive immediate postoperative radiotherapy or undergo active surveillance.
Historically, decisions have relied predominantly on retrospective studies, with conflicting conclusions regarding recurrence prevention.
The new randomized evidence strengthens the rationale for offering adjuvant radiotherapy to patients who prioritize reducing recurrence risk.
Nevertheless, the investigators emphasized that treatment decisions should remain individualized.
Approximately 70% of patients assigned to observation remained free from meningioma recurrence during the median follow-up period, meaning some patients may avoid radiotherapy without experiencing recurrence.
Patient age, comorbidities, tumor location, potential for repeat surgery, anticipated radiation exposure, and individual preferences remain important considerations.
Several limitations should also be recognized. Twelve patients assigned to radiotherapy did not receive their allocated treatment, the prespecified number of primary endpoint events was not reached, and long-term quality-of-life data were incomplete. Additionally, five tumors would now be classified as WHO grade 3 based on molecular alterations under the 2021 classification.
A Potential Practice-Changing Trial in Meningioma Management
The ROAM/EORTC-1308 trial provides the strongest prospective evidence to date supporting adjuvant radiotherapy after complete surgical resection of WHO grade 2 atypical meningioma.
By improving five-year disease-free survival from 64.3% to 79.9%, postoperative IMRT demonstrated a meaningful reduction in recurrence risk without a detected deterioration in quality of life or neurocognitive outcomes during the available follow-up.
These findings support considering adjuvant radiotherapy as an important postoperative treatment option for patients with completely resected atypical meningioma, while emphasizing shared decision-making and individualized assessment of recurrence risk and potential long-term toxicity.
Further randomized evidence from the ongoing NRG BN003 trial, together with longer follow-up and molecularly informed risk stratification, may help refine patient selection and optimize postoperative treatment strategies.
