title: Anticipated intraoperative electron beam boost, external beam radiation therapy, and limb-sparing surgical resection for patients with pediatric soft-tissue sarcomas of the extremity: a multicentric pooled analysis of long-term outcomes.
abstract: OBJECTIVE
  To perform a joint analysis of data from 3 contributing centers within the intraoperative electron-beam radiation therapy (IOERT)-Spanish program, to determine the potential of IOERT as an anticipated boost before external beam radiation therapy in the multidisciplinary treatment of pediatric extremity soft-tissue sarcomas.
  
  
  METHODS
  From June 1993 to May 2013, 62 patients (aged <21 years) with a histologic diagnosis of primary extremity soft-tissue sarcoma with absence of distant metastases, undergoing limb-sparing grossly resected surgery, external beam radiation therapy (median dose 40 Gy) and IOERT (median dose 10 Gy) were considered eligible for this analysis.
  
  
  RESULTS
  After a median follow-up of 66 months (range, 4-235 months), 10-year local control, disease-free survival, and overall survival was 85%, 76%, and 81%, respectively. In multivariate analysis after adjustment for other covariates, tumor size >5 cm (P=.04) and R1 margin status (P=.04) remained significantly associated with local relapse. In regard to overall survival only margin status (P=.04) retained association on multivariate analysis. Ten patients (16%) reported severe chronic toxicity events (all grade 3).
  
  
  CONCLUSIONS
  An anticipated IOERT boost allowed for external beam radiation therapy dose reduction, with high local control and acceptably low toxicity rates. The combined radiosurgical approach needs to be tested in a prospective trial to confirm these results.
authors.affiliation: Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid, Spain; School of Medicine, Complutense University, Madrid, Spain; Service of Radiation Oncology, Instituto de Radiomedicina, Santiago, Chile. Electronic address: cvsole@uc.cl.
authors.forename: Claudio V
authors.initials: CV
authors.lastname: Sole
authors.affiliation: Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid, Spain; School of Medicine, Complutense University, Madrid, Spain.
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Calvo
authors.affiliation: Service of Radiation Oncology, Hospital Universitario Ramón y Cajal, Madrid, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Polo
authors.affiliation: Service of Radiation Oncology, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Cambeiro
authors.affiliation: Service of Radiation Oncology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Alvarez
authors.affiliation: Service of Radiation Oncology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Gonzalez
authors.affiliation: Service of Pediatric Orthopedics and Traumatology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Jose
authors.initials: J
authors.lastname: Gonzalez
authors.affiliation: Service of Orthopedics and Traumatology, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Mikel
authors.initials: M
authors.lastname: San Julian
authors.affiliation: Service of Radiation Oncology, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Martinez-Monge
mesh_terms: D000293:Adolescent; D002423:Cause of Death; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual / Q000706:statistics & numerical data; D018450:Disease Progression; D018572:Disease-Free Survival; D004583:Electrons / Q000627:therapeutic use*; D005121:Extremities; D005260:Female; D005354:Fibrosarcoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D051677:Histiocytoma, Malignant Fibrous / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D015999:Multivariate Analysis; D059351:Organ Sparing Treatments / Q000379:methods; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D020266:Radiotherapy, Conformal / Q000379:methods; D012509:Sarcoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018234:Sarcoma, Alveolar Soft Part / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D013584:Sarcoma, Synovial / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D047368:Tumor Burden; D055815:Young Adult