title: Evaluation of a new concept for the management of skull base chordomas and chondrosarcomas.
abstract: OBJECTIVE
  Chordomas and chondrosarcomas of the skull base are rare locally invasive tumors associated with high recurrence rates. The aim of this study was to evaluate the concept of microsurgical tumor volume reduction followed by early gamma knife surgery (GKS).
  
  
  METHODS
  Thirteen patients with 15 tumors were treated between October 2000 and June 2003. There were three patients (23.1%) with chordomas and 10 (76.9%) with chondrosarcomas. There were nine men and four women who ranged in age between 19 and 69 years. All patients first underwent maximal tumor resection. Within 2 to 10 months after surgery they were treated with GKS. The mean postoperative tumor volume treated with GKS was 9.7 cm3 (range 1.4-20.3 cm3). Follow-up computerized tomography and magnetic resonance imaging examinations with volumetric tumor analysis were performed every 6 months after GKS. The mean treatment dose was 17 Gy and the mean isodose was 52%. The mean follow-up duration was 17 months during which there was only one tumor recurrence at the margin of the radiation field. The mean volume reduction was 35.4%.
  
  
  CONCLUSIONS
  Results of this treatment strategy are encouraging but the efficacy of this multimodal treatment combining surgery and early GKS requires a longer follow up.
authors.affiliation: International Neuroscience Institute Hannover, Germany. feigl@ini-hannover.de
authors.forename: Guenther Christian
authors.initials: GC
authors.lastname: Feigl
authors.forename: Otto
authors.initials: O
authors.lastname: Bundschuh
authors.forename: Alireza
authors.initials: A
authors.lastname: Gharabaghi
authors.forename: Sam
authors.initials: S
authors.lastname: Safavi-Abassi
authors.forename: Amr
authors.initials: A
authors.lastname: El Shawarby
authors.forename: Madjid
authors.initials: M
authors.lastname: Samii
authors.forename: Gerhard A
authors.initials: GA
authors.lastname: Horstmann
mesh_terms: D000328:Adult; D000368:Aged; D002817:Chordoma / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000295:instrumentation*; D012189:Retrospective Studies; D019292:Skull Base Neoplasms / Q000473:pathology / Q000601:surgery*