Results from the international ROAM trial, published today in The Lancet and presented at EANO 2026 (Meeting of the European Association of Neuro-Oncology), give people with atypical meningioma clear evidence to guide one of the hardest decisions after surgery.

Who this news is for?

Meningiomas are tumours that grow from the membranes covering the brain. Most are grade 1, so non malignant (sometimes called “benign” or “typical”). They grow slowly, and after surgery they are usually just monitored with scans. This news is not about grade 1 meningioma, and nothing changes for people with that diagnosis.

This news is about atypical meningioma, which is grade 2. It makes up around one in five meningiomas. Even when the surgeon removes all of the tumour they can see, atypical meningioma is more likely to come back.

The question people have faced until now

After successful surgery, people with atypical meningioma have had to choose between two options:

• having radiotherapy straight away to lower the chance of the tumour returning, or
• “active surveillance”: regular MRI scans, with treatment only if the tumour comes back.

Until today, nobody knew which was better. UK, European and US guidelines said either option was reasonable. Those guidelines rested on small, older studies that disagreed with each other, so the choice often depended on which hospital you went to, which doctor you saw and what your own choice was.

A question more than a decade in the making

The researchers set out to answer this question more than ten years ago. The question was deliberately simple. If all of the visible tumour has been removed, does radiotherapy straight away reduce the risk of it coming back, compared with careful monitoring?

What did the ROAM trial do?

ROAM is the first trial anywhere in the world to answer this properly. It was led by Professor Michael Jenkinson, the lead investigator. It ran at 58 hospitals in 11 countries, led from Liverpool with European and Australian partners. It included 157 people whose atypical meningioma had been fully removed. Each person was allocated at random to one of two groups:

• radiotherapy (30 treatments over six weeks), or
• active surveillance (watch and wait).

Everyone was then followed for more than five years on average. Every radiotherapy plan was checked centrally before treatment began, so the quality of treatment was consistent across all the hospitals.

What did the trial find?

• Radiotherapy roughly halved the risk of the tumour coming back. Recurrence happened in about 1 in 7 people who had radiotherapy, compared with about 3 in 10 people who were monitored.
• Five years after surgery, around 8 in 10 people in the radiotherapy group were free of recurrence, compared with around 6 in 10 in the watch-and-wait group.
• Quality of life, memory and thinking showed no clear differences between the groups. Fewer people completed these assessments in later years, so the researchers say this needs longer follow-up.
• Side effects were mostly mild. Nearly half of the people who had radiotherapy had short-term side effects, most often scalp redness, hair loss, tiredness and headaches. About a quarter had longer-lasting effects, mainly persistent hair loss, headache and fatigue. Serious side effects were uncommon, and no one died because of treatment.
• The benefit held up across tumour types. Tissue testing showed that radiotherapy reduced recurrence whatever the tumour’s molecular make-up.

Why not just wait and treat it if it comes back?

This was one of the questions raised at EANO. The researchers explained that treating a tumour once it has returned is often less effective. It can mean more surgery, more radiotherapy, or both, and that takes a toll on quality of life. Some atypical meningiomas also become more aggressive when they come back.

Why this matters: it is practice-changing

For the first time, people with atypical meningioma and their clinical teams have high-quality evidence to base this decision on. The results are expected to shape national and international treatment guidelines. Radiotherapy after complete removal of an atypical meningioma should now be seriously considered and offered, rather than left to chance.

It does not mean radiotherapy for everyone

The researchers were clear about this at EANO. The trial shows that radiotherapy works. It does not mean every person should have it. In the trial, 7 in 10 people who were monitored did not see their tumour return within five years.

Your team should still talk through what is right for you, taking into account:

• your preferences
• your age and general health,
• any existing memory or thinking difficulties,
• where the tumour was, and whether it could be removed again easily if it came back, and
• how large an area would need radiotherapy.

The difference now is that this conversation can be backed by solid evidence.

Shaped by patients

People affected by meningioma helped design and run ROAM from the start, and patient members sat on the trial’s management and steering groups. When the trial was designed, patients said radiotherapy would only be worth six weeks of treatment and its side effects if it at least halved the risk of recurrence. That is what the trial found.

brainstrust is proud to have been part of this work. Our co-founder, Dr Helen Bulbeck, is a co-author of the paper.

“For years, people with atypical meningioma have been asked to make a big decision without clear evidence. ROAM changes that. Patients told the researchers what benefit would make radiotherapy worthwhile, and the trial has delivered it. Now every person facing this choice deserves an informed conversation with their team.” Helen Bulbeck

What happens next

The team hopes to keep following trial participants over the next 10 to 15 years to understand the very long-term effects of radiotherapy. A similar trial in the US is due to report in the 2030s. Its results will eventually be combined with ROAM’s.

What should I do if I have atypical meningioma?

• If you are newly diagnosed, ask your team whether radiotherapy is recommended for you, and why.
• If you chose active surveillance in the past, there is no need to worry, and you should not stop your scans. Raise these results at your next appointment if you would like to talk them through.
• If you’re not sure whether your meningioma is grade 1 or grade 2, ask your team. Remember that these results apply only to grade 2.

We’re here for you

If this news raises questions, or you want help getting ready for a conversation with your team, get in touch us via email at hello@brainstrust.org.uk.

The full paper, “Radiotherapy versus observation following surgical resection of WHO grade 2 atypical meningioma (ROAM/EORTC-1308)”, is open access in The Lancet, which can be accessed here.