title: A comprehensive analysis of intracranial chordoma and survival: a systematic review.
abstract: OBJECTIVE
  Despite the published information on cranial chordoma, most of the data regarding survival in these patients has come from a single institution. Here, we perform a systematic review of the literature to evaluate across multiple institutions the overall survival after treatment for intracranial chordoma.
  
  
  METHODS
  We systematically analysed every study published in English and found a total of over 2000 patients being treated for intracranial chordoma. The overall 5-year and 10-year survivals in these patients were stratified according to the age (<5 years vs. >5 years and  <40 years vs. >40 years), treatment (surgery and radiation vs. surgery alone) and histological findings (chondroid vs. typical). Data were analysed via Pearson chi-square test and student t-test when appropriate.
  
  
  RESULTS
  A total of 560 non-duplicated patients treated for cranial chordoma met inclusion criteria for this systematic analysis. The survival rate among these patients was 63% (299 patients) and 16% (176 patients) for 5-year and 10-year survivals, respectively. There was no difference in overall survival between the two groups when a cut-off age of 40 years was used (<40 years = 50% vs.  >40 years = 51% at 5-year survival; p = 0.1), but when 5 years was used as the cut-off age, then survival was better for patients in the group older than 5 years of age (<5 years = 14% vs.  >5 years = 66%; p = 0.001). There was no difference between 5-year survival in patients with chordoma with histological chondroid features and those with chordoma possessing typical histology (45% vs. 67%; p = 0.06). When patients who only received surgery were compared to those patients who were treated with surgical intervention in combination with adjuvant radiation treatment, no difference in survival rate was found (54% vs. 56% at 5 years; p = 0.8).
  
  
  CONCLUSIONS
  The results of our systematic study provide data to predict the survival of intracranial chordoma patients across multiple institutions. Our data suggest that patients younger than 5 years of age may be associated with a worse prognosis, and adjuvant radiation therapy and histological type were not associated with the improvement of survival rates.
authors.affiliation: Department of Neurological Surgery, University of California at San Francisco, San Francisco, California, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Jian
authors.forename: Orin G
authors.initials: OG
authors.lastname: Bloch
authors.forename: Isaac
authors.initials: I
authors.lastname: Yang
authors.forename: Seunggu J
authors.initials: SJ
authors.lastname: Han
authors.forename: Derrick
authors.initials: D
authors.lastname: Aranda
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Parsa
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001932:Brain Neoplasms / Q000401:mortality / Q000532:radiotherapy / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D002817:Chordoma / Q000401:mortality / Q000532:radiotherapy / Q000601:surgery*; D006801:Humans; D007223:Infant; D008875:Middle Aged; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D016019:Survival Analysis; D016896:Treatment Outcome