title: Preliminary results of high-dose single-fraction radiotherapy for the management of chordomas of the spine and sacrum.
abstract: BACKGROUND
  En bloc wide-margin excision significantly decreases the risk of chordoma recurrence. However, a wide surgical margin cannot be obtained in many chordomas because they arise primarily in the sacrum, clivus, and mobile spine. Furthermore, these tumors have shown resistance to fractionated photon radiation at conventional doses and numerous chemotherapies.
  
  
  OBJECTIVE
  To analyze the outcomes of single-fraction stereotactic radiosurgery (SRS) in the treatment of chordomas of the mobile spine and sacrum.
  
  
  METHODS
  Twenty-four patients with chordoma of the sacrum and mobile spine were treated with high-dose single-fraction SRS (median dose, 2400 cGy). Twenty-one primary and 3 metastatic tumors were treated. Seven patients were treated for postoperative tumor recurrence. In 7 patients, SRS was administered as planned adjuvant therapy, and in 13 patients, SRS was administered as neoadjuvant therapy. All patients had serial magnetic resonance imaging follow-up.
  
  
  RESULTS
  The overall median follow-up was 24 months. Of the 24 patients, 23 (95%) demonstrated stable or reduced tumor burden based on serial magnetic resonance imaging. One patient had radiographic progression of tumor 11 months after SRS. Only 6 of 13 patients who underwent neoadjuvant SRS proceeded to surgery. This decision was based on the lack of radiographic progression and the patient's preference. Complications were limited to 1 patient in whom sciatic neuropathy developed and 1 with vocal cord paralysis.
  
  
  CONCLUSIONS
  High-dose single-fraction SRS provides good tumor control with low treatment-related morbidity. Additional follow-up is required to determine the long-term recurrence risk.
authors.affiliation: Departments of †Radiation Oncology, ‡Neurosurgery, §Medical Physics, and ¶Orthopedics, Memorial Sloan-Kettering Cancer Center, New York, New York; ‖Department of Neurologic Surgery, Weill Cornell Medical College, New York, New York; #Departments of Medicine, Pediatrics, and Orthopedics, Mount Sinai School of Medicine, New York, New York.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Yamada
authors.forename: Ilya
authors.initials: I
authors.lastname: Laufer
authors.forename: Brett W
authors.initials: BW
authors.lastname: Cox
authors.forename: D Michael
authors.initials: DM
authors.lastname: Lovelock
authors.forename: Robert G
authors.initials: RG
authors.lastname: Maki
authors.forename: Joan M
authors.initials: JM
authors.lastname: Zatcky
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Boland
authors.forename: Mark H
authors.initials: MH
authors.lastname: Bilsky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002817:Chordoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000532:radiotherapy; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D012447:Sacrum / Q000473:pathology*; D013125:Spinal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D016896:Treatment Outcome