title: Photon-based fractionated stereotactic radiotherapy for postoperative treatment of skull base chordomas.
abstract: OBJECTIVE
  We report our series of skull base chordoma patients who underwent surgical resection followed by high-dose fractionated stereotactic radiotherapy (FSRT) as an alternative to proton radiotherapy (RT).
  
  
  METHODS
  Between 2002 and 2009, 12 patients with skull base chordomas without prior radiation history were treated with adjuvant or salvage RT. FSRT with dynamic conformal arcs and intensity-modulated radiation therapy boost was used until 2006 when image-guided intensity-modulated FSRT was instituted. Median dose of 66.6 Gy (range, 48.6 to 68.4 Gy) was delivered in 180 cGy fractions prescribed to the 90% isodose line that covered the target volume to achieve a median isocenter dose of 74 Gy (range, 54 to 76 Gy).
  
  
  RESULTS
  Median follow-up was 42 months. Median time from surgery to initiation of RT was 3.6 months. Overall survival was 76.4% at 5 years, and 46.9% and 37.5% of patients were free of progression at 24 and 60 months, respectively. Six patients had disease progression after radiation with a median time to progression of 17.3 months. One patient was salvaged with radiosurgery and surgical resection, with stable disease almost 7 years since diagnosis. Two patients were salvaged with molecular targeted therapy with stable disease at 20 and 23 months. At last follow-up, 9 patients had stable or reduced disease.
  
  
  CONCLUSIONS
  FSRT as postoperative treatment of skull base chordomas resulted in promising overall survival results comparable with the published literature of particle therapy without significant complications. Our technique for treating skull base chordomas can be considered a safe and less costly alternative to proton RT.
authors: Department of Radiation Oncology, Kaiser Permanente, Los Angeles, CA 90027, USA. darlenebugoci@yahoo.com
authors: Darlene M
authors: DM
authors: Bugoci
authors: Michael R
authors: MR
authors: Girvigian
authors: Joseph C T
authors: JC
authors: Chen
authors: Michael M
authors: MM
authors: Miller
authors: Javad
authors: J
authors: Rahimian
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D002817:Chordoma / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D015331:Cohort Studies; D016208:Databases, Factual; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D011182:Postoperative Care / Q000379:methods; D016634:Radiosurgery / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D019292:Skull Base Neoplasms / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D016019:Survival Analysis; D016896:Treatment Outcome