title: Use of proton therapy for re-irradiation in pediatric intracranial ependymoma.
abstract: OBJECTIVE
  To report disease control, survival and treatment-associated toxicity with the use of proton therapy (PRT) for re-irradiation of intracranial ependymoma.
  
  
  METHODS
  Twenty patients underwent 33 PRT re-irradiation courses for recurrent or metastatic lesions between June 2004 and February 2015 at Massachusetts General Hospital.
  
  
  RESULTS
  The majority of patients were female (60%), with infratentorial tumors (90%), anaplastic histology (55%), and initially received 55.8 GyRBE (52.2-59.4) involved field (IF) PRT. First failure was local (55%), distant (30%) or both (15%) at a median time of 23.9 months (9.9-98.5) from first treatment. Salvage therapy included re-resection (75%), chemotherapy (60%) and IFPRT (70%) to a median dose 50.4 GyRBE (35-55.8) in the majority of patients. The median follow-up was 37.8 months (5.5-138.0). Three year OS and PFS are 78.6% (95% CI 67.6-89.6) and 28.1% (95% CI 15.6-40.6), respectively. Longer OS was significantly associated with surgical resection of recurrent disease (HR 9.19, 95% CI 1.27-66.44, p=0.028). The pattern of second failure after re-irradiation was directly related to the pattern of first failure (p<0.01). Three of 14 patients (21.4%) locally re-treated experienced grade 2 radiation-associated treatment change.
  
  
  CONCLUSIONS
  Proton therapy appears safe and efficacious for the re-treatment of recurrent intracranial ependymoma.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA.
authors.forename: Bree R
authors.initials: BR
authors.lastname: Eaton
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA.
authors.forename: Varun
authors.initials: V
authors.lastname: Chowdhry
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Weaver
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Pediatrics, Massachusetts General Hospital, Boston, USA.
authors.forename: David
authors.initials: D
authors.lastname: Ebb
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: MacDonald
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA.
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Tarbell
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, USA. Electronic address: tyock@partners.org.
authors.forename: Torunn I
authors.initials: TI
authors.lastname: Yock
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D004806:Ependymoma / Q000401:mortality / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D061766:Proton Therapy; D000069475:Re-Irradiation
keywords: Ependymoma; Pediatric; Proton; Radiotherapy; Re-irradiation