• Conditions Treated

  • Arteriovenous Malformation
  • Bone Metastases
  • Brain Tumors
    • Gliomas
    • Brain Metastases
    • Pituitary Adenoma
    • Meningioma
    • Acoustic Neuroma
  • Kidney Tumors
  • Liver Tumors
  • Lung Tumors
  • Ocular / Orbital Tumors
  • Pancreatic Cancer
  • Prostate Cancer
  • Spinal Tumors
  • Trigeminal Neuralgia

Meningioma

Though classified as brain tumors, meningiomas are located on the brain surface rather than within brain tissue. They occur mostly in female patients and are believed to grow from the meningeal layer of membranes between the skull and the brain.

Meningiomas account for about 15 percent of brain tumors, and nearly all – about 97 percent – are benign, while the remaining 3 percent can have malignant features. Most meningiomas grow slowly and can become quite large before they’re detected. Most go unnoticed until they cause neurological problems like headaches, seizures or impaired brain functions.

Most meningiomas occur randomly, and their origins are unknown. There are familial links with meningiomas for a small number of patients who suffer genetic disorders like neurofibromatosis or multiple meningiomatosis. Meningiomas are more common in females – a 4-to-1 ratio compared to males – and older patients, peaking in the age range of 50 to 70 years. Some researchers believe post-menopausal hormonal changes may contribute to higher rates of meningiomas among women.

Meningiomas can occur anywhere within the skull or around the spinal cord. Some entrap nerves and blood vessels, making tumor treatment more difficult. This is often the case for skull-base meningiomas, since most of the critical arteries and nerves are located along the base of the skull.

What are the treatment options?

Treatment for meningiomas falls into four broad categories:

• Stereotactic radiosurgery
• Watchful waiting
• Surgical removal
• Conventional radiation therapy

Stereotactic radiosurgery

Stereotactic radiosurgery with the CyberKnife uses highly focused and precisely aimed radiation beams that destroy the tumor while sparing the nearby healthy tissue. The success rate of stereotactic radiosurgery is very high – about 95 percent of meningiomas stop growing after one treatment or a small series of treatments. The risks of radiosurgery include a relatively small chance the tumor will continue growing despite treatment, as well as a small risk that the radiation injures healthy nerves next to the tumor.

Overall, these risks are low and substantially less than microsurgical removal, especially for skull-base meningiomas. Most medical centers report excellent tumor control rates after radiosurgery – about 90 percent to 95 percent. The risk of neurological injury depends on the tumor location.

There are several instances in which radiosurgery isn’t the best option for treating meningiomas, particularly larger tumors. Cases must be evaluated individually, but many radiosurgery centers are reluctant to treat meningiomas larger than 3.5 centimeters in diameter. Larger meningiomas often press against the brain and produce symptoms. Surgical removal is uniquely able to promptly decompress the brain and restore neurological function. Moreover, if doctors suspect the tumor is not a meningioma, they may recommend a biopsy or surgical removal for an accurate diagnosis.

One drawback of radiosurgery is that it destroys the tumor without allowing a diagnosis. Therefore, doctors must be reasonably confident of the diagnosis based solely on imaging like MRI or CT scans to recommend radiosurgery as a first-line treatment. Patients who undergo surgery in which parts of the tumor are not removed or those who experience tumor regrowth generally don’t need a biopsy again prior to CyberKnife radiosurgery.

For meningiomas not located in the skull base, the risk of temporary radiation injury is about 2 percent to 3 percent, while the risk of permanent radiation injury is about 1 percent. These rates are slightly higher for larger tumors and skull-base meningiomas.

If patients have clinical symptoms like headaches, double vision or seizures, among others, these likely will improve after radiosurgery, though improvements typically take several months or even years.

A major advantage of CyberKnife is that, unlike other radiosurgical systems, it doesn’t require a metal frame screwed into the patient’s skull to perform treatment. The CyberKnife’s ability to offer staged, or fractionated, treatment is another significant advantage. In those cases, treatment is spread over two to five smaller sessions. This makes it possible to more safely treat some meningiomas that are larger or those located next to critical structures like the optic nerve.

Watchful waiting

Watchful waiting involves carefully observing the tumor over time with MRI scans every six to 12 months. Obviously, this is not an option for patients with large symptomatic tumors. Since they’re slow growing, however, this is a reasonable option for elderly patients or those with significant medical problems when smaller meningiomas are found. The main disadvantage of watchful waiting is that the difficulty and risks of treatment increase as the tumor grows.

Surgical removal

Surgical removal, known as resection, has many advantages. If the meningioma can be completely removed and is benign, the cure rate is very high. Surgery also provides tissue to confirm a diagnosis. The disadvantages include common drawbacks of open brain surgery – bleeding, strokes, impaired brain function and infections. Meningiomas around the skull base carry the highest risks. Complete surgical removal of skull-base meningiomas often isn’t possible, and there is substantial risk of regrowth.

Conventional radiation therapy

Conventional radiation therapy is generally used to treat malignant meningiomas that are often spread out and difficult to localize, or when treating meningiomas that are too large for radiosurgery. For most meningiomas, treatment with conventional radiation is not as aggressive or successful as radiosurgery, and therefore, represents a second line of therapy.