title: Spot-scanning proton radiation therapy for pediatric chordoma and chondrosarcoma: clinical outcome of 26 patients treated at paul scherrer institute.
abstract: OBJECTIVE
  To evaluate the clinical results of fractionated spot-scanning proton radiation therapy (PT) in 26 pediatric patients treated at Paul Scherrer Institute for chordoma (CH) or chondrosarcoma (CS) of the skull base or axial skeleton.
  
  
  METHODS
  Between June 2000 and June 2010, 19 CH and 7 CS patients with tumors originating from the skull base (17) and the axial skeleton (9) were treated with PT. Mean age at the time of PT was 13.2 years. The mean prescribed dose was 74 Gy (relative biological effectiveness [RBE]) for CH and 66 Gy (RBE) for CS, at a dose of 1.8-2.0 Gy (RBE) per fraction.
  
  
  RESULTS
  Mean follow-up was 46 months. Actuarial 5-year local control (LC) rates were 81% for CH and 80% for CS. Actuarial 5-year overall survival (OS) was 89% for CH and 75% for CS. Two CH patients had local failures: one is alive with evidence of disease, while the other patient succumbed to local recurrence in the surgical pathway. One CS patient died of local progression of the disease. No high-grade late toxicities were observed.
  
  
  CONCLUSIONS
  Spot-scanning PT for pediatric CH and CS patients resulted in excellent clinical outcomes with acceptable rates of late toxicity. Longer follow-up time and larger cohort are needed to fully assess tumor control and late effects of treatment.
authors.affiliation: Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Rombi
authors.forename: Carmen
authors.initials: C
authors.lastname: Ares
authors.forename: Eugen B
authors.initials: EB
authors.lastname: Hug
authors.forename: Ralf
authors.initials: R
authors.lastname: Schneider
authors.forename: Gudrun
authors.initials: G
authors.lastname: Goitein
authors.forename: Adrian
authors.initials: A
authors.lastname: Staab
authors.forename: Francesca
authors.initials: F
authors.lastname: Albertini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bolsi
authors.forename: Antony J
authors.initials: AJ
authors.lastname: Lomax
authors.forename: Beate
authors.initials: B
authors.lastname: Timmermann
mesh_terms: D000293:Adolescent; D001859:Bone Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D002813:Chondrosarcoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D002817:Chordoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D061766:Proton Therapy / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D012062:Relative Biological Effectiveness; D019292:Skull Base Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D013557:Switzerland; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult