title: Intensity modulated radiation therapy provides excellent local control in high-risk abdominal neuroblastoma.
abstract: BACKGROUND
  Locoregional failure is a significant concern in patients with high-risk abdominal neuroblastoma (NB) receiving radiotherapy. Locoregional control outcomes were studied in children with NB receiving intensity modulated radiotherapy (IMRT).
  
  
  METHODS
  Twenty children (11 females, 9 males) with NB (median age at diagnosis 3.4 years) receiving IMRT were analyzed for locoregional failure, outcomes, and toxicities. IMRT doses were 23.4 Gy (n = 12), 30 Gy (n = 1), 30.6 Gy (n = 5), and 36.0 Gy (n = 2) based on extent of resection. Five patients had tumors with MYCN amplification, and 19 had metastatic disease. All patients were treated consistently using reproducible immobilization techniques; physiological motion was assessed by 4D-CT, and target localization by cone-beam computed tomography. ICRU 62 volumetric conventions were employed based on institutional data for pediatric target volume and organ motion.
  
  
  RESULTS
  No patient developed primary site infield or locoregional failure at a median follow-up of 2.2 years. Distant failure (median time to distant failure 1.6 years) occurred in the brain, lungs, or skeletal sites in eight patients, five of whom died. The 2-year event-free survival was 58.5 ± 13.3% and cumulative incidence of local and distant failures was 0% and 41.5 ± 11.9%, respectively. Asymptomatic loose stool during RT occurred in nearly all patients, but required no intervention.
  
  
  CONCLUSIONS
  IMRT is feasible, safe in the short term, and yields excellent locoregional control. Despite subtotal resection in some cases, locoregional control appeared to be increased by conformal radiotherapy with ICRU 62-compliant volumes. Dose escalation beyond 30.6 Gy may be unnecessary with improved target volume coverage.
authors.affiliation: Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, USA. atmaram.pai-panandiker@stjude.org
authors.forename: Atmaram S
authors.initials: AS
authors.lastname: Pai Panandiker
authors.forename: Chris
authors.initials: C
authors.lastname: Beltran
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Billups
authors.forename: Lisa M
authors.initials: LM
authors.lastname: McGregor
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Furman
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Davidoff
mesh_terms: D000008:Abdominal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D000071447:N-Myc Proto-Oncogene Protein; D009362:Neoplasm Metastasis; D009447:Neuroblastoma / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D009687:Nuclear Proteins / Q000235:genetics; D015513:Oncogene Proteins / Q000235:genetics; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins