title: Prognostic factors in the operative management of dedifferentiated sacral chordomas.
abstract: BACKGROUND
  Dedifferentiated chordomas are rare high-grade malignant spinal tumors for which there is minimal information to help guide treatment.
  
  
  OBJECTIVE
  To identify prognostic factors associated with increased risk of local recurrence, metastases, and reduced survival in a cohort of patients undergoing sacrectomy for de novo dedifferentiated sacral chordoma.
  
  
  METHODS
  Ten patients undergoing sacrectomy for histologically confirmed dedifferentiated chordoma at a specialist center were reviewed. There were 6 male and 4 female patients with a mean age of 66.7 years (range, 57-80 years) and mean follow-up of 36.7 months (range, 3-98 months). Data on prognostic factors were collected.
  
  
  RESULTS
  The commonest presenting symptom was lumbar/gluteal pain. Mean duration of preoperative symptoms was 3.6 months (range, 2-7 months). Local recurrence was seen in 7 patients; metastases occurred in 5 patients. After sacrectomy, 7 patients died at a mean of 41 months (range, 3-98 months). Tumor size >10 cm in diameter, amount of dedifferentiation within the conventional chordoma, sacroiliac joint infiltration, and inadequate resection margins were associated with increased risk of recurrence and reduced survival. Surgical approach, cephalad extent of primary tumor, and adjuvant radiotherapy did not affect oncological outcomes.
  
  
  CONCLUSIONS
  Dedifferentiated chordomas are aggressive malignant tumors with a higher risk of local recurrence, metastases, and early mortality than conventional chordomas. Tumor diameter >10 cm, marginal resection, and sacroiliac joint infiltration may be associated with increased risk of local recurrence and mortality. Those with a smaller burden of dedifferentiated disease (<1 cm) within the primary chordoma have a better prognosis. Patients should be counseled about these risks before surgery and should have regular follow-up for the detection of local recurrence and metastases.
authors.affiliation: The Royal National Orthopaedic Hospital, Stanmore, United Kingdom.
authors.forename: Babar
authors.initials: B
authors.lastname: Kayani
authors.forename: Mathew D
authors.initials: MD
authors.lastname: Sewell
authors.forename: Sammy A
authors.initials: SA
authors.lastname: Hanna
authors.forename: Asif
authors.initials: A
authors.lastname: Saifuddin
authors.forename: William
authors.initials: W
authors.lastname: Aston
authors.forename: Robin
authors.initials: R
authors.lastname: Pollock
authors.forename: John
authors.initials: J
authors.lastname: Skinner
authors.forename: Sean
authors.initials: S
authors.lastname: Molloy
authors.forename: Timothy W R
authors.initials: TW
authors.lastname: Briggs
mesh_terms: D000368:Aged; D002817:Chordoma / Q000401:mortality / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000401:mortality / Q000473:pathology; D019635:Neurosurgical Procedures; D011379:Prognosis; D012189:Retrospective Studies; D012447:Sacrum; D013125:Spinal Neoplasms / Q000401:mortality / Q000601:surgery*; D016896:Treatment Outcome