Meningioma (Brain & Spine Membrane Tumor), from the CureRays guide library.

Meningioma is the most common tumor of the brain and spine and is usually benign — many are simply watched, and when treatment is needed, focused radiation, including a single-session radiosurgery, can control them precisely while protecting the brain.

What it is.

A meningioma is a tumor that grows from the meninges, the thin protective membranes that wrap around the brain and spinal cord. It is the most common primary tumor of the central nervous system, and the large majority are benign (non-cancerous), slow-growing, and well-behaved. Because a meningioma arises from the covering rather than from the brain itself, it tends to push on the brain or spinal cord from the outside rather than invading through it, which is part of why so many can be controlled or even cured. Many meningiomas are found by chance on a scan done for another reason and never cause any symptoms. When they do cause problems, it is usually because of where they sit and what they press on: headaches, seizures, weakness, vision or hearing changes, or — for ones along the spine — back pain, numbness, or weakness in the limbs. They are more common in women and become more common with age. The behavior of a meningioma depends heavily on its grade. Most are grade 1 (benign and slow). A smaller number are grade 2 (atypical), which are more likely to come back, and a few are grade 3 (malignant/anaplastic), which behave aggressively. Because most meningiomas grow slowly and many never cause trouble, a common and appropriate first step — especially for small, symptom-free tumors found incidentally — is careful monitoring with periodic scans. When treatment is needed, the main tools are surgery and radiation, and these are often complementary: surgery removes what it safely can, and precise radiation controls what remains or treats tumors in locations too risky to operate on.

How radiation treats it.

Radiation therapy controls a meningioma by delivering precisely targeted energy that damages the DNA inside the tumor cells, so they lose the ability to grow and divide. Because most meningiomas grow slowly, the goal of radiation is usually long-term control — stopping the tumor from enlarging and, over time, often shrinking it — rather than a sudden disappearance. The defining feature of modern radiation for meningiomas is precision. In stereotactic radiosurgery, many beams are aimed from different directions so they all cross at the tumor; each beam alone is gentle, but together they deliver a strong dose right at the target, and the dose drops off so sharply at the edges that the surrounding brain receives very little. This allows a meningioma to be treated in a single session or a few sessions, often without an incision, which is why radiosurgery is so valuable for tumors at the skull base — wrapped around nerves, blood vessels, or the brainstem — where surgery would be dangerous. For larger tumors, or ones sitting right against a sensitive structure like the optic nerve, the dose is instead divided into several smaller daily treatments (fractionated radiotherapy), which lets those delicate tissues recover between sessions while still controlling the tumor. Radiation is used in several ways: as the primary treatment for tumors that cannot be safely removed, as an addition after surgery for higher-grade tumors or when removal was incomplete, and to treat tumors that come back. Long-term control rates for benign meningiomas treated with focused radiation are very high — often well above 90% at ten years — and because the surrounding brain is protected, most people keep their neurological function. Proton therapy, where available, can further reduce dose to healthy tissue beyond the tumor, an advantage for large skull-base tumors and younger patients.

The ways we can treat it.

Stereotactic radiosurgery (SRS). Many precisely aimed beams converge on the tumor to deliver a high dose in a single session (or a few sessions), with the dose falling off sharply at the edges so the surrounding brain is largely spared — ideal for small-to-moderate and skull-base meningiomas.

Fractionated stereotactic radiotherapy (FSRT). The same precise targeting delivered as several smaller daily treatments, preferred when a tumor is larger or sits right next to a sensitive structure such as the optic nerve, allowing those tissues to tolerate the treatment safely.

Postoperative (adjuvant) radiation. After surgery for a grade 2 or 3 tumor, or when a benign tumor could not be fully removed, radiation to the tumor bed lowers the chance the meningioma returns.

Proton therapy in selected cases. Proton beams deposit their dose and then stop, reducing radiation to healthy brain beyond the target — valuable for larger skull-base tumors and for younger patients where limiting lifetime exposure matters.

Questions we hear often.

My scan found a meningioma but I feel fine — do I need treatment? Often not right away. Many meningiomas are found by chance, are small, and grow very slowly, so a common and appropriate first step is active surveillance — periodic MRI scans to see whether it changes. Treatment is recommended if the tumor grows or starts to cause symptoms. Watching it closely avoids the risks of treatment for a tumor that may never need any.

What is radiosurgery, and is it actually surgery? Despite the name, stereotactic radiosurgery involves no cutting. It uses many precisely aimed radiation beams that converge on the tumor to deliver a strong dose in a single session (or a few), while sparing the surrounding brain. It is especially useful for small-to-moderate meningiomas and for tumors at the skull base that would be dangerous to remove with an operation.

Will radiation harm my brain? Modern focused radiation is designed to protect the healthy brain. The dose is concentrated on the tumor and falls off sharply at the edges, and when a tumor is larger or near a sensitive area like the optic nerve, the treatment is divided into several smaller sessions so those tissues tolerate it well. Most people keep their neurological function, and serious side effects are uncommon.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.