title: Initial clinical experience with image-guided linear accelerator-based spinal radiosurgery for treatment of benign nerve sheath tumors.
abstract: BACKGROUND
  Stereotactic radiosurgery has proven a safe and effective treatment of cranial nerve sheath tumors. A similar approach should be successful for histologically identical spinal nerve sheath tumors.
  
  
  METHODS
  The preliminary results of linear accelerator-based spinal radiosurgery were retrospectively reviewed for a group of 25 nerve sheath tumors. Tumor location was cervical 11, lumbar 10, and thoracic 4. Thirteen tumors caused sensory disturbance, 12 pain, and 9 weakness. Tumor size varied from 0.9 to 4.1 cm (median, 2.1 cm). Radiosurgery was performed with a 60-MV linear accelerator equipped with a micro-multileaf collimator. Median peripheral dose and prescription isodose were 12 Gy and 90%, respectively. Image guidance involved optical tracking of infrared reflectors, fusion of amorphous silicon radiographs with dynamically reconstructed digital radiographs, and automatic patient positioning. Follow-up varied from 12 to 58 months (median, 18).
  
  
  RESULTS
  There have been no local failures. Tumor size remained stable in 18 cases, and 7 (28%) demonstrated more than 2 mm reduction in tumor size. Of 34 neurologic symptoms, 4 improved. There has been no clinical or imaging evidence for spinal cord injury. One patient had transient increase in pain and one transient increase in numbness.
  
  
  CONCLUSIONS
  Results of this limited experience indicate linear accelerator-based spinal radiosurgery is feasible for treatment of benign nerve sheath tumors. Further follow-up is necessary, but our results imply spinal radiosurgery may represent a therapeutic alternative to surgery for nerve sheath tumors. Symptom resolution may require a prescribed dose of more than 12 Gy.
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-6951, USA. mselch@mednet.ucla.edu
authors.forename: Michael T
authors.initials: MT
authors.lastname: Selch
authors.forename: Kevin
authors.initials: K
authors.lastname: Lin
authors.forename: Nzhde
authors.initials: N
authors.lastname: Agazaryan
authors.forename: Steve
authors.initials: S
authors.lastname: Tenn
authors.forename: Alessandra
authors.initials: A
authors.lastname: Gorgulho
authors.forename: John J
authors.initials: JJ
authors.lastname: DeMarco
authors.forename: Antonio A F
authors.initials: AA
authors.lastname: DeSalles
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000601:surgery; D009442:Neurilemmoma / Q000175:diagnosis / Q000601:surgery*; D009456:Neurofibromatosis 1 / Q000175:diagnosis / Q000601:surgery; D016518:Neurofibromatosis 2 / Q000175:diagnosis / Q000601:surgery; D009460:Neurologic Examination; D010524:Peripheral Nervous System Neoplasms / Q000175:diagnosis / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis; D016634:Radiosurgery / Q000295:instrumentation*; D013127:Spinal Nerves / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D055815:Young Adult