title: Skull base chondrosarcoma radiosurgery: report of the North American Gamma Knife Consortium.
abstract: OBJECTIVE
  Stereotactic radiosurgery (SRS) is a potentially important option for patients with skull base chondrosarcomas. The object of this study was to analyze the outcomes of SRS for chondrosarcoma patients who underwent this treatment as a part of multimodality management.
  
  
  METHODS
  Seven participating centers of the North American Gamma Knife Consortium (NAGKC) identified 46 patients who underwent SRS for skull base chondrosarcomas. Thirty-six patients had previously undergone tumor resections and 5 had been treated with fractionated radiation therapy (RT). The median tumor volume was 8.0 cm3 (range 0.9-28.2 cm3), and the median margin dose was 15 Gy (range 10.5-20 Gy). Kaplan-Meier analysis was used to calculate progression-free and overall survival rates.
  
  
  RESULTS
  At a median follow-up of 75 months after SRS, 8 patients were dead. The actuarial overall survival after SRS was 89% at 3 years, 86% at 5 years, and 76% at 10 years. Local tumor progression occurred in 10 patients. The rate of progression-free survival (PFS) after SRS was 88% at 3 years, 85% at 5 years, and 70% at 10 years. Prior RT was significantly associated with shorter PFS. Eight patients required salvage resection, and 3 patients (7%) developed adverse radiation effects. Cranial nerve deficits improved in 22 (56%) of the 39 patients who deficits before SRS. Clinical improvement after SRS was noted in patients with abducens nerve paralysis (61%), oculomotor nerve paralysis (50%), lower cranial nerve dysfunction (50%), optic neuropathy (43%), facial neuropathy (38%), trochlear nerve paralysis (33%), trigeminal neuropathy (12%), and hearing loss (10%).
  
  
  CONCLUSIONS
  Stereotactic radiosurgery for skull base chondrosarcomas is an important adjuvant option for the treatment of these rare tumors, as part of a team approach that includes initial surgical removal of symptomatic larger tumors.
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia;
authors.forename: Jason
authors.initials: J
authors.lastname: Sheehan
authors.affiliation: Departments of Radiation Oncology and Neurological Surgery, University of California, San Francisco, San Francisco, California;
authors.forename: Penny K
authors.initials: PK
authors.lastname: Sneed
authors.affiliation: Departments of Radiation Oncology and Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona;
authors.forename: Heyoung L
authors.initials: HL
authors.lastname: McBride
authors.affiliation: Department of Neurological Surgery, University of Kentucky, Lexington, Kentucky;
authors.forename: Byron
authors.initials: B
authors.lastname: Young
authors.affiliation: Department of Neurological Surgery, Hoag Memorial Hospital, Newport Beach, California;
authors.forename: Christopher
authors.initials: C
authors.lastname: Duma
authors.affiliation: Department of Neurological Surgery, Université de Sherbrooke, Centre de Recherche Clinique Étienne-LeBel, Sherbrooke, Quebec, Canada;
authors.forename: David
authors.initials: D
authors.lastname: Mathieu
authors.affiliation: Departments of Radiation Oncology and Neurological Surgery, University of California, San Francisco, San Francisco, California;
authors.forename: Zachary
authors.initials: Z
authors.lastname: Seymour
authors.affiliation: Departments of Radiation Oncology and Neurological Surgery, University of California, San Francisco, San Francisco, California;
authors.forename: Michael W
authors.initials: MW
authors.lastname: McDermott
authors.affiliation: Department of Neurological Surgery, New York University Langone Medical Center, New York, New York; and.
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.affiliation: Department of Neurological Surgery, Stanford University, Stanford, California.
authors.forename: Aditya
authors.initials: A
authors.lastname: Iyer
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania;
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002813:Chondrosarcoma / Q000473:pathology / Q000601:surgery*; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000453:epidemiology / Q000209:etiology; D009656:North America; D011182:Postoperative Care; D011183:Postoperative Complications / Q000453:epidemiology; D016634:Radiosurgery / Q000379:methods*; D019292:Skull Base Neoplasms / Q000473:pathology / Q000601:surgery*; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
keywords: ARE = adverse radiation effects; EORTC = European Organization for Research and Treatment of Cancer; Gamma Knife; NAGKC = North American Gamma Knife Consortium; PFS = progression-free survival; PTV = (SRS) planning tumor volume; RT = fractionated radiation therapy; RTOG = Radiation Therapy Oncology Group; SRS = stereotactic radiosurgery; UPMC = University of Pittsburgh Medical Center; chondrosarcoma; oncology; skull base tumor; stereotactic radiosurgery