Stereotactic radiation is effective as surgery against nerve tumor

Oct 31 2007

Specifically aimed, "stereotactic" radiation may be as good as surgery - and in some cases, even better - in treating benign but potentially devastating brain tumors called non-acoustic schwannomas, according to a study by rradiation oncologists at the Kimmel Cancer Center at Thomas Jefferson University and Thomas Jefferson University Hospital in Philadelphia.

While surgery – the standard treatment – is effective and the only way to remove the tumor, it's tricky and can potentially damage surrounding cranial nerves, including those associated with facial movement, eyesight and hearing. Some non-acoustic schwannomas wrap around various structures in the brain and cannot be completely removed. Treating the tumor with radiation is usually effective, less risky, and the vast majority of tumors do not grow back, notes Maria Werner-Wasik, M.D., associate professor of Radiation Oncology at Jefferson Medical College of Thomas Jefferson University.

Timothy Showalter, M.D., a resident in Radiation Oncology, Dr. Werner-Wasik, David Andrews, M.D., professor of Neurological Surgery at Jefferson Medical College, and their co-workers identified 39 patients with non-acoustic schwannomas who received radiation therapy at Thomas Jefferson University Hospital from 1996 to 2007. Patients either received stereotactic radiosurgery (SRS), which entails precise delivery of a single, focused, high dose of radiation to a specific area of the brain, or fractionated stereotactic radiation (FSR), where treatments are received over days or weeks. Roughly one-half of the patients had surgery to remove part of the tumor before radiation; the other half had only radiation. They found that stereotactic radiation, whether delivered in a single dose or in many doses over time, provided “excellent local tumor control.

“We found that we can improve the symptoms whether they get a single dose of radiation or several smaller doses, and it seems to be permanent, with few bad side effects,” Dr. Werner-Wasik says. “That would be extremely unlikely to expect with a surgical approach.” They report their results on October 30, 2007 at the annual meeting of the American Society for Therapeutic Radiology and Oncology in Los Angeles.

Radiation has always been used in addition to surgery. But, Dr. Werner-Wasik points out, “The use of stereotactic radiation allows safer use of radiation and can be applied in a wider variety of patients. While the standard of care has been surgery for most patients, the pendulum is swinging to radiation becoming the new standard as an initial treatment.”

Dr. Showalter notes that the team would like to conduct trials testing the effectiveness of smaller doses of radiation, and examine which radiation type is more effective.

Schwannomas form on cranial nerves in the brain. Symptoms vary, depending on which cranial nerves are affected, and can include headache, hearing loss, facial pain or numbness, muscle weakness, difficulty swallowing and double vision. Non-acoustic schwannomas are rare, representing about 10 percent of the approximately 3,000 cases of schwannomas that occur annually in the United States.