title: Impact of cytogenetic abnormalities on the management of skull base chordomas.
abstract: OBJECTIVE
  Cytogenetic studies of chordomas are scarce and show multiple changes involving different chromosomes. These abnormalities are implicated in the pathogenesis of chordoma, but the clinical significance of these changes is yet to be determined. In this study, the authors discuss the cytogenetic changes in a large series of skull base chordomas with long-term follow-up and focus on the impact of these changes on the prognosis, progression, and management of the disease.
  
  
  METHODS
  The karyotypes of chordomas in 64 patients (36 men and 28 women) were studied in relation to survival and recurrence or progression over a mean follow-up period of 48 +/- 37.5 months. The standard G-banding technique was used for karyotype analysis. Statistical analysis was performed with the Fisher exact test and ORs, and Kaplan-Meier curves were generated for survival and recurrence/progression of disease.
  
  
  RESULTS
  Seventy-four percent of de novo chordomas had normal karyotypes and a 3% recurrence rate; there was a 45% recurrence rate in de novo tumors with abnormal karyotypes (p < 0.01). Recurrent tumors were associated with a high incidence of abnormal karyotype (75%). The OR for recurrence in lesions with an abnormal versus a normal karyotype was 12. Aberrations in chromosomes 3, 4, 12, 13, and 14 were associated with frequent recurrence and decreased survival time. Ninety-five percent of cases with progression involved chromosome 3 and/or 13. The median survival time was 4 months when both of these chromosomes had aberrations (p = 0.02).
  
  
  CONCLUSIONS
  Chordomas with normal karyotypes were associated with a low rate of recurrence and a long patient survival, and recurrent chordomas were associated with an abnormal karyotype, disease progression, and poor survival. De novo chordomas with normal karyotypes may be amenable to radical resection and adjunctive proton beam therapy. Recurrent and de novo chordomas with abnormal karyotypes were associated with complex cytogenetic abnormalities and a poor prognosis, particularly in the presence of aberrations underlying tumor progression in chromosomes 3, 4, 12, 13, and 14.
authors.affiliation: Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA. kkalmefty@uams.edu
authors.forename: Kaith K
authors.initials: KK
authors.lastname: Almefty
authors.forename: Svetlana
authors.initials: S
authors.lastname: Pravdenkova
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Sawyer
authors.forename: Ossama
authors.initials: O
authors.lastname: Al-Mefty
mesh_terms: D000328:Adult; D002817:Chordoma / Q000235:genetics* / Q000401:mortality; D002869:Chromosome Aberrations; D018450:Disease Progression; D005260:Female; D006801:Humans; D007621:Karyotyping; D008297:Male; D009364:Neoplasm Recurrence, Local; D019292:Skull Base Neoplasms / Q000235:genetics* / Q000401:mortality