title: Nasopharyngeal carcinoma: repeat treatment with conformal proton therapy--dose-volume histogram analysis.
abstract: OBJECTIVE
  To analyze control, survival, and complication rates of conformal proton radiation for recurrent nasopharyngeal carcinoma.
  
  
  METHODS
  Sixteen patients with nasopharyngeal carcinoma initially treated with 50.0-88.2 Gy photons were re-treated with protons to additional doses of 59.4-70.2 CGE. Local-regional control and survival were correlated with extent of relapse, recurrence versus persistence, and prescribed dose and were subjected to dose-volume histogram analysis. Mean follow-up was 23.7 months (range, 4-47 months).
  
  
  RESULTS
  Twenty-four-month actuarial overall and local-regional progression-free survival rates were both 50%. The 24-month actuarial overall survival rates for patients with "optimal" dose-volume histogram coverage versus "suboptimal" coverage were 83% and 17%, respectively (P = .006). Doses to critical structures were low (0-22.0 Gy); no central nervous system side effects supervened.
  
  
  CONCLUSIONS
  Adequate tumor coverage, as evaluated by using dose-volume histogram analysis, was found to be the most important variable influencing local-regional control and survival. No central nervous system complications were observed; increases in the dose to adjacent critical structures are being evaluated.
authors.affiliation: Department of Radiation Medicine, Loma Linda University Medical Center, CA 92354, USA.
authors.forename: R
authors.initials: R
authors.lastname: Lin
authors.forename: J D
authors.initials: JD
authors.lastname: Slater
authors.forename: L T
authors.initials: LT
authors.lastname: Yonemoto
authors.forename: R I
authors.initials: RI
authors.lastname: Grove
authors.forename: S L
authors.initials: SL
authors.lastname: Teichman
authors.forename: D K
authors.initials: DK
authors.lastname: Watt
authors.forename: J M
authors.initials: JM
authors.lastname: Slater
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000532:radiotherapy*; D011379:Prognosis; D015996:Survival Rate