title: Dose-response in radiotherapy for localized prostate cancer: results of the Dutch multicenter randomized phase III trial comparing 68 Gy of radiotherapy with 78 Gy.
abstract: OBJECTIVE
  To determine whether a dose of 78 Gy improves outcome compared with a conventional dose of 68 Gy for prostate cancer patients treated with three-dimensional conformal radiotherapy.
  
  
  METHODS
  Between June 1997 and February 2003, stage T1b-4 prostate cancer patients were enrolled onto a multicenter randomized trial comparing 68 Gy with 78 Gy. Patients were stratified by institution, age, (neo)adjuvant hormonal therapy (HT), and treatment group. Four treatment groups (with specific radiation volumes) were defined based on the probability of seminal vesicle involvement. The primary end point was freedom from failure (FFF). Failure was defined as clinical failure or biochemical failure, according to the American Society of Therapeutic Radiation Oncology definition. Other end points were freedom from clinical failure (FFCF), overall survival (OS), and toxicity.
  
  
  RESULTS
  Median follow-up time was 51 months. Of the 669 enrolled patients, 664 were included in the analysis. HT was prescribed for 143 patients. FFF was significantly better in the 78-Gy arm compared with the 68-Gy arm (5-year FFF rate, 64% v 54%, respectively), with an adjusted hazard ratio of 0.74 (P = .02). No significant differences in FFCF or OS were seen between the treatment arms. There was no difference in late genitourinary toxicity of Radiation Therapy Oncology Group and European Organisation for Research and Treatment of Cancer grade 2 or more and a slightly higher nonsignificant incidence of late gastrointestinal toxicity of grade 2 or more.
  
  
  CONCLUSIONS
  This multicenter randomized trial shows a significantly improved FFF in prostate cancer patients treated with a higher dose of radiotherapy.
authors.affiliation: Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors.forename: Stephanie T H
authors.initials: ST
authors.lastname: Peeters
authors.forename: Wilma D
authors.initials: WD
authors.lastname: Heemsbergen
authors.forename: Peter C M
authors.initials: PC
authors.lastname: Koper
authors.forename: Wim L J
authors.initials: WL
authors.lastname: van Putten
authors.forename: Annerie
authors.initials: A
authors.lastname: Slot
authors.forename: Michel F H
authors.initials: MF
authors.lastname: Dielwart
authors.forename: Johannes M G
authors.initials: JM
authors.lastname: Bonfrer
authors.forename: Luca
authors.initials: L
authors.lastname: Incrocci
authors.forename: Joos V
authors.initials: JV
authors.lastname: Lebesque
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage; D016896:Treatment Outcome