The use of fractionated stereotactic radiotherapy (FSR) on patients with optic nerve sheath meningiomas results in less vision loss than when patients are treated with conventional surgery, based on a study presented today at the annual meeting of the American Society for Radiation Oncology in Chicago.

Optic nerve sheath meningiomas are rare benign tumors of the optic nerve. Approximately 65 percent of cases occur in middle-age females, and is more common in older adults (mean age 44.7 years).

According to Robert Den, MD, a radiation oncology resident at Thomas Jefferson University Hospital in Philadelphia, and colleagues, this type of radiotherapy is a more precise, targeted type of radiation therapy that spares surrounding tissue while allowing an effective radiation dose to hit the tumor.

The researchers conducted a retrospective analysis of 58 patients with optic nerve sheath meningiomas who were treated with FSR between 1996 and 2006. They reviewed patient charts for technical radiotherapy information and patient outcomes—including local control, visual acuity and toxicity related to treatment.

Den and colleagues found that the radiographic local tumor control was more than 95 percent. Visual acuity was stabilized or improved in 92 percent of patients, while four patients had worsening vision. One patient developed optic neuritis and one developed central retinal venous occlusion.

"This was the largest U.S. cohort of patients with optic nerve sheath meningiomas treated with fractionated stereotactic radiotherapy," said Den. "There is no difference in outcome and the patients' quality of life was much better. This should be the standard of care for patients with optic nerve sheath meningiomas."