title: Ocular preservation after 36 Gy external beam radiation therapy for retinoblastoma.
abstract: OBJECTIVE
  The purpose of this study was to document the ocular preservation rate after 36 Gy external beam radiation therapy (EBRT) for retinoblastoma.
  
  
  METHODS
  Forty-nine eyes of 38 patients were treated with a median dose of 36 Gy EBRT. The patient population included 7 unilateral and 31 bilateral presentations, with a median age at diagnosis of 4 months. Eyes enucleated at the time of diagnosis or treated with other measures were not included in the analysis of ocular preservation. The median age at EBRT was 8 months. Patients were monitored for progression of disease after EBRT and second malignant neoplasms.
  
  
  RESULTS
  The median follow-up was 88.6 months, with an estimated ocular preservation rate of 82.0% +/- 5% at 10 years. There was a difference in the ocular preservation rates for patients with advanced disease (Reese-Ellsworth group III-V) compared with early disease. Metastatic disease developed in two patients, and a second malignant neoplasm developed in three. Patients treated with en face electrons experienced a lower 5-year estimate of ocular preservation than those treated with photons, although patients treated with electrons were more likely to have advanced disease.
  
  
  CONCLUSIONS
  The use of low-dose EBRT (36 Gy) results in ocular preservation rates that are comparable to those of high-dose EBRT. The use of electrons requires careful treatment planning and computerized dosimetry.
authors.affiliation: Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. thomas.merchant@stjude.org
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Merchant
authors.forename: Ciara J
authors.initials: CJ
authors.lastname: Gould
authors.forename: Nathan E
authors.initials: NE
authors.lastname: Hilton
authors.forename: Larry E
authors.initials: LE
authors.lastname: Kun
authors.forename: Carlos
authors.initials: C
authors.lastname: Rodríguez-Galindo
authors.forename: Charles B
authors.initials: CB
authors.lastname: Pratt
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Wilson
authors.forename: Barrett
authors.initials: B
authors.lastname: Haik
mesh_terms: D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009362:Neoplasm Metastasis / Q000473:pathology / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D019572:Retinal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D012175:Retinoblastoma / Q000473:pathology / Q000532:radiotherapy*; D012189:Retrospective Studies; D016896:Treatment Outcome