title: Mobile spine chordoma: results of 166 patients from the AOSpine Knowledge Forum Tumor database.
abstract: OBJECTIVE
  A chordoma is an indolent primary spinal tumor that has devastating effects on the patient's life. These lesions are chemoresistant, resistant to conventional radiotherapy, and moderately sensitive to proton therapy; however, en bloc resection remains the preferred treatment for optimizing patient outcomes. While multiple small and largely retrospective studies have investigated the outcomes following en bloc resection of chordomas in the sacrum, there have been few large-scale studies on patients with chordomas of the mobile spine. The goal of this study was to review the outcomes of surgically treated patients with mobile spine chordomas at multiple international centers with respect to local recurrence and survival. This multiinstitutional retrospective study collected data between 1988 and 2012 about prognosis-predicting factors, including various clinical characteristics and surgical techniques for mobile spine chordoma. Tumors were classified according to the Enneking principles and analyzed in 2 treatment cohorts: Enneking-appropriate (EA) and Enneking-inappropriate (EI) cohorts. Patients were categorized as EA when the final pathological assessment of the margin matched the Enneking recommendation; otherwise, they were categorized as EI.
  
  
  METHODS
  Descriptive statistics were used to summarize the data (Student t-test, chi-square, and Fisher exact tests). Recurrence and survival data were analyzed using Kaplan-Meier survival curves, log-rank tests, and multivariate Cox proportional hazard modeling.
  
  
  RESULTS
  A total of 166 patients (55 female and 111 male patients) with mobile spine chordoma were included. The median patient follow-up was 2.6 years (range 1 day to 22.5 years). Fifty-eight (41%) patients were EA and 84 (59%) patients were EI. The type of biopsy (p < 0.001), spinal location (p = 0.018), and if the patient received adjuvant therapy (p < 0.001) were significantly different between the 2 cohorts. Overall, 58 (35%) patients developed local recurrence and 57 (34%) patients died. Median survival was 7.0 years postoperative: 8.4 years postoperative for EA patients and 6.4 years postoperative for EI patients (p = 0.023). The multivariate analysis showed that the EI cohort was significantly associated with an increased risk of local recurrence in comparison with the EA cohort (HR 7.02; 95% CI 2.96-16.6; p < 0.001), although no significant difference in survival was observed.
  
  
  CONCLUSIONS
  EA resection plays a major role in decreasing the risk for local recurrence in patients with chordoma of the mobile spine.
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Ziya L
authors.initials: ZL
authors.lastname: Gokaslan
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Zadnik
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sciubba
authors.affiliation: Research Department, AOSpine International, Davos, Switzerland;
authors.forename: Niccole
authors.initials: N
authors.lastname: Germscheid
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: C Rory
authors.initials: CR
authors.lastname: Goodwin
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Wolinsky
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Chetan
authors.initials: C
authors.lastname: Bettegowda
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Mari L
authors.initials: ML
authors.lastname: Groves
authors.affiliation: Section for Oncological Orthopaedics and Reconstruction of the Spine, IRCCS Istituto Orthopedico Galeazzi, Milan, Italy;
authors.forename: Alessandro
authors.initials: A
authors.lastname: Luzzati
authors.affiliation: Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas;
authors.forename: Laurence D
authors.initials: LD
authors.lastname: Rhines
authors.affiliation: Department of Orthopaedics, Division of Spine, University of British Columbia and Vancouver Coastal Health, Vancouver, British Columbia, Canada;
authors.forename: Charles G
authors.initials: CG
authors.lastname: Fisher
authors.affiliation: National Center for Spinal Disorders and Buda Health Center, Budapest, Hungary;
authors.forename: Peter Pal
authors.initials: PP
authors.lastname: Varga
authors.affiliation: Department of Orthopaedic Surgery, The CORE Institute, Sun City West, Arizona;
authors.forename: Mark B
authors.initials: MB
authors.lastname: Dekutoski
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota;
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Clarke
authors.affiliation: Department of Surgery, Division of Neurosurgery and Spinal Program, University of Toronto and Toronto Western Hospital, Toronto, Ontario, Canada;
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
authors.affiliation: Centre for Spinal Studies and Surgery, Queen's Medical Centre, Nottingham University Hospital NHS Trust, Nottingham, United Kingdom;
authors.forename: Nasir A
authors.initials: NA
authors.lastname: Quraishi
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, California;
authors.forename: Dean
authors.initials: D
authors.lastname: Chou
authors.affiliation: Spinal Division, Nuffield Orthopedic Centre, University of Oxford, United Kingdom;
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Reynolds
authors.affiliation: Department of Orthopaedics, Princess Alexandra Hospital, Brisbane, Australia;
authors.forename: Richard P
authors.initials: RP
authors.lastname: Williams
authors.affiliation: Department of Orthopedic Surgery, Kanazawa University, Kanazawa, Japan; and.
authors.forename: Norio
authors.initials: N
authors.lastname: Kawahara
authors.affiliation: Department of Oncologic and Degenerative Spine Surgery, Rizzoli Orthopaedic Institute, Bologna, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Boriani
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002817:Chordoma / Q000401:mortality / Q000601:surgery*; D003131:Combined Modality Therapy / Q000379:methods; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000601:surgery*; D018714:Radiotherapy, Adjuvant / Q000379:methods; D012189:Retrospective Studies; D012447:Sacrum / Q000473:pathology*; D013125:Spinal Neoplasms / Q000401:mortality / Q000601:surgery*; D016896:Treatment Outcome
keywords: EA = Enneking appropriate; EI = Enneking inappropriate; Enneking classification; chordoma; mobile spine; oncology; recurrence; surgery; survival; tumor