title: Clinical outcome of anaplastic thyroid carcinoma treated with radiotherapy of once- and twice-daily fractionation regimens.
abstract: BACKGROUND
  The purpose was to assess local control, survival, and toxicity after radiotherapy in patients with anaplastic thyroid carcinoma, and to compare clinical outcomes between once-daily and twice-daily fractionation regimens.
  
  
  METHODS
  A retrospective review of patients with anaplastic thyroid carcinoma (n = 47) who underwent external beam radiotherapy from 1983 to 2004 was conducted. Twenty-three patients underwent radical radiotherapy with a radiation dose > 40 Gy, and 24 patients underwent palliative radiotherapy with a dose < or = 40 Gy. Of radical radiotherapy, radiation was given with once-daily (14 patients) or twice-daily fractionation (9 patients; 1.5 Gy per fraction) to a total dose of 45-66 Gy. Most patients (37 patients; 78.7%) were followed to death.
  
  
  RESULTS
  The 6-month local progression-free rate in patients who underwent radical radiotherapy was 94.1%, significantly higher compared with palliative radiotherapy (64.6%; P = .02). The median actuarial overall survival was greater in patients with radical radiotherapy (11.1 months) compared with palliative radiotherapy (3.2 months; P < .0001). The median overall survival in patients with twice-daily fractionation (13.6 months) was 3.3 months longer than patients treated with once-daily fractionation (10.3 months), but the difference was not statistically significant (P = .3). For patients treated with twice-daily fractionation, 3 patients had Grade 3 acute skin toxicity, and no patient had Grade 3 or higher esophageal toxicity.
  
  
  CONCLUSIONS
  Radiotherapy can result in local control of anaplastic thyroid carcinoma. A twice-daily fractionation regimen is well tolerated and has a trend to longer survival, which deserves a larger study.
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada.
authors.forename: Yongjin
authors.initials: Y
authors.lastname: Wang
authors.forename: Richard
authors.initials: R
authors.lastname: Tsang
authors.forename: Sylvia
authors.initials: S
authors.lastname: Asa
authors.forename: Brendan
authors.initials: B
authors.lastname: Dickson
authors.forename: Tamara
authors.initials: T
authors.lastname: Arenovich
authors.forename: James
authors.initials: J
authors.lastname: Brierley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000401:mortality / Q000532:radiotherapy*; D018450:Disease Progression; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000453:epidemiology; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016879:Salvage Therapy; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D016896:Treatment Outcome