title: Proton radiotherapy for pediatric central nervous system germ cell tumors: early clinical outcomes.
abstract: OBJECTIVE
  To report early clinical outcomes for children with central nervous system (CNS) germ cell tumors treated with protons; to compare dose distributions for intensity-modulated photon radiotherapy (IMRT), three-dimensional conformal proton radiation (3D-CPT), and intensity-modulated proton therapy with pencil beam scanning (IMPT) for whole-ventricular irradiation with and without an involved-field boost.
  
  
  METHODS
  All children with CNS germinoma or nongerminomatous germ cell tumor who received treatment at the Massachusetts General Hospital between 1998 and 2007 were included in this study. The IMRT, 3D-CPT, and IMPT plans were generated and compared for a representative case.
  
  
  RESULTS
  Twenty-two patients were treated with 3D-CPT. At a median follow-up of 28 months, there were no CNS recurrences; 1 patient had a recurrence outside the CNS. Local control, progression-free survival, and overall survival rates were 100%, 95%, and 100%, respectively. Comparable tumor volume coverage was achieved with IMRT, 3D-CPT, and IMPT. Substantial normal tissue sparing was seen with any form of proton therapy as compared with IMRT. The use of IMPT may yield additional sparing of the brain and temporal lobes.
  
  
  CONCLUSIONS
  Preliminary disease control with proton therapy compares favorably to the literature. Dosimetric comparisons demonstrate the advantage of proton radiation over IMRT for whole-ventricle radiation. Superior dose distributions were accomplished with fewer beam angles utilizing 3D-CPT and scanned protons. Intensity-modulated proton therapy with pencil beam scanning may improve dose distribution as compared with 3D-CPT for this treatment.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. smacdonald@partners.org
authors.forename: Shannon M
authors.initials: SM
authors.lastname: MacDonald
authors.forename: Alexei
authors.initials: A
authors.lastname: Trofimov
authors.forename: Sairos
authors.initials: S
authors.lastname: Safai
authors.forename: Judith
authors.initials: J
authors.lastname: Adams
authors.forename: Barbara
authors.initials: B
authors.lastname: Fullerton
authors.forename: David
authors.initials: D
authors.lastname: Ebb
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Tarbell
authors.forename: Torunn I
authors.initials: TI
authors.lastname: Yock
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D002648:Child; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D018237:Germinoma / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D006801:Humans; D008297:Male; D009373:Neoplasms, Germ Cell and Embryonal / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011379:Prognosis; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult; D011522:Protons
chemical_list: D011522:Protons