UF Studies New Treatment For Rare Nerve Tumor

February 19, 1999

GAINESVILLE—University of Florida physicians have successfully treated a group of patients suffering from a rare skull-base tumor using an advanced radiation treatment system.

In a study in the current International Journal of Radiation Oncology, Biology and Physics, 18 patients with non-acoustic schwannomas benign tumors which form on cranial nerves exiting from the brain were treated with a safer, less-expensive alternative to cranial surgery using a machine called a stereotactic linear accelerator, said John Buatti, an associate professor of radiation oncology at UF’s Brain Institute.

“Our findings show tumors have been controlled in 100 percent of the patients, with a low complication rate,” said Buatti. “Surgical alternatives often may pose a greater risk of nerve injury in these cases.”

Developed by UF researchers in 1986, the linear accelerator, or linac, uses a computer model of patients’ brains to direct multiple arcs of tightly focused X-rays to brain lesions. What results is a high dose of radiation where these beams intersect with only minimal amounts reaching healthy brain tissue.

Since 1988, UF has used the noninvasive, outpatient technique to treat more than 1,200 patients for brain tumors and intracranial disorders.

Schwannomas form on the sheath surrounding nerves. Symptoms vary by patient, depending on which cranial nerves are affected, and can include headache, hearing loss, facial pain or numbness, muscle weakness, difficulty swallowing and double vision.

Typically, non-acoustic schwannomas are removed surgically. Though effective at controlling tumors, surgery may pose a significant risk to cranial nerves including those associated with facial movement, eyesight and hearing. Some patients, including the elderly and medically unstable, cannot undergo cranial surgery because of the potential complications. In this study, UF neurosurgeons and oncologists stabilized or decreased the size of the schwannoma in each instance and none of the patients required surgery for complications.

Preliminary findings using stereotactic radiosurgery for non-acoustic schwannomas have been “very encouraging,” said Sheilaine Mabanta, a UF radiation oncology resident and one of the primary researchers on the study, who added that many patients’ symptoms improved. Even so, she and Buatti agreed surgery is still an effective and excellent treatment for many non-acoustic schwannomas.

“Surgery is the proven treatment as long as the neurosurgeon can remove the tumor without severe complications,” Mabanta said.