Playing Catch-Up With Meningiomas
Date: January 3, 2010
In the early 20th century, neurosurgical pioneer Harvey Cushing described a type of slow-growing brain tumor that develops from the meninges, the thin protective membranes that cover the brain and spinal cord. Appropriately enough, he called the tumors .
Cushing, whose early career bloomed at Johns Hopkins, introduced revolutionary, safer surgical techniques for removing the growths. Since then, the surgery continues to improve, says neurosurgeon Alessandro Olivi, a modern-day keeper of Cushing’s flame.
“Advances in technology and in understanding the anatomy of these tumors allow us to be more aggressive in our surgical approach,” Olivi explains. In addition, more than one surgical avenue now exists.
Conventional surgery is still best for easily accessible tumors, he says. But meningiomas at the base of the skull, near cranial nerves and often-torturous blood vessels, have always posed a challenge. Recently, in selected cases, Hopkins neurosurgeons have begun using scalpel-less radiosurgery, either on its own or to supplement the traditional approach.
Though radiosurgery isn’t new, applying it to skull-base operations is, and calls for a higher level of precision. After consulting three-dimensional images of a patient’s brain to mark precise tumor location, surgeons direct highly focused radiation at the site. Dose and number of sessions vary, depending on the size and location of the tumor. At Hopkins, the procedure is performed as an outpatient service in a dedicated site, not in the OR.
Thanks to that improvement, the prognosis for meningioma is brighter, says Olivi. Still, he and his colleagues see a need to refine and add to what’s available.
Because, for example, no effective chemotherapy exists for meningioma, a team headed by Gregory Riggins has stepped up the quest for candidate drugs. As an oncology researcher within the neurosurgery department — one of few in the field — Riggins has begun seeking drugs that are not only safe to use with radiation but that can also complement its effects.
Finally, there’s the problem of meningiomas-inwaiting. Not all of the tumors require surgery or treatment of any kind, says Olivi. Of the 90% that are benign, many are so unobtrusive that they go undetected until a patient happens to have an MRI or CT scan for another reason. On occasion, however, some begin growing quickly. They press on the brain, leaving headaches, seizures, or more serious problems such as stroke in their wake. And a small number, about 3-5% , become malignant.
How do you decide which ones will pose a problem? That’s the challenge, Olivi explains. Imaging, so far, can’t help. Even biopsy, presently, can’t foresee benign meningiomas with malignant potential.
Their DNA, however, might offer clues. In the future, Olivi and Riggins plan studies to identify genetic characteristics of meningiomas that predict aggression. Having better prognostic tools, Olivi says, will help inform surgeons’ decisions.
For information, contact the Johns Hopkins Neurosurgery at 410-955-0703.