title: En bloc resection for primary and metastatic tumors of the spine: a systematic review of the literature.
abstract: BACKGROUND
  The efficacy of en bloc resection for spinal tumors is unknown because most of the current evidence is provided by small, single-institution clinical series or case reports.
  
  
  OBJECTIVE
  To combine all previously published reports of en bloc resection for primary and metastatic spinal tumors, to describe the overall pattern of disease-free survival, and to investigate potentially prognostic factors for recurrence.
  
  
  METHODS
  A complete MEDLINE search for all articles reporting survival data for en bloc resection of spinal tumors was undertaken; 44 articles met inclusion criteria from which 306 eligible patients were identified.
  
  
  RESULTS
  There were 229 cases of primary tumors with a mean follow-up of 65.0 months and 77 cases of solitary metastatic tumors with a mean follow-up of 26.5 months. Median time to recurrence was 113 months for the primary group and 24 months for the metastatic group. Disease-free survival rates at 1, 5, and 10 years were 92.6%, 63.2%, and 43.9%, respectively, for the primary group and 61.8%, 37.5%, and 0%, respectively, for the metastatic group; 5-year disease-free survival rates were 58.4% for chordoma and 62.9% for chondrosarcoma. After adjusting for covariates, age, male sex, metastatic tumors, and osteosarcomas were significantly associated with a tumor recurrence.
  
  
  CONCLUSIONS
  This study provides the largest published series of patients undergoing en bloc resection for spinal tumors. Median time to recurrence reached almost 10 years in patients with primary tumors; however, it was only 2 years in those with isolated metastatic tumors.
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, San Francisco, California 94143, USA.
authors.forename: Jordan M
authors.initials: JM
authors.lastname: Cloyd
authors.forename: Frank L
authors.initials: FL
authors.lastname: Acosta
authors.forename: Mei-Yin
authors.initials: MY
authors.lastname: Polley
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D019635:Neurosurgical Procedures; D011379:Prognosis; D016016:Proportional Hazards Models; D013125:Spinal Neoplasms / Q000556:secondary* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult