title: Phase II study of hypofractionated image-guided radiotherapy for localized prostate cancer: outcomes of 55 Gy in 16 fractions at 3.4 Gy per fraction.
abstract: OBJECTIVE
  To estimate the late morbidity of a novel, hypofractionated external beam radiotherapy schedule of 55 Gy in 16 fractions (4 fractions/week, 3.4 Gy per fraction) for localized prostate cancer.
  
  
  METHODS
  A multi-center phase 2 study enrolled seventy-three patients between September 2004 and June 2006. After insertion of fiducial gold markers, they were treated with image-guidance (IGRT) using conformal techniques with intensity-modulation, if necessary, and then followed every 6 months for toxicity rating and PSA. Patient reported outcomes were collected yearly. Median follow up was 4.6 years.
  
  
  RESULTS
  At 4 years post-radiotherapy, the cumulative incidence of combined urinary and bowel grade 3 toxicity was 7% (95% CI 3-16%) and grade 2+ was 33% (95% CI 24-46%). All except two patients recovered from their grade 3 events. Patient-reported reduction of function was most pronounced at year two for urinary function (mean -7, SD 16), and at year one for bowel function (mean -7, SD 21). The cumulative incidence of biochemical (PSA nadir+2) or biopsy-proven relapse at 4 years was 9% (95% CI 4-18%).
  
  
  CONCLUSIONS
  Hypofractionated radiotherapy is clinically feasible and more convenient than conventional schedules for patients with localized prostate cancer. Phase 3 multicenter studies are on-going (NCT00126165).
authors.affiliation: Department of Oncology, University of Calgary, Alberta, Canada. jackson.wu@albertahealthservices.ca
authors.forename: Jackson S Y
authors.initials: JS
authors.lastname: Wu
authors.forename: Penelope M A
authors.initials: PM
authors.lastname: Brasher
authors.forename: Ali
authors.initials: A
authors.lastname: El-Gayed
authors.forename: Nadeem
authors.initials: N
authors.lastname: Pervez
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Tai
authors.forename: John
authors.initials: J
authors.lastname: Robinson
authors.forename: David
authors.initials: D
authors.lastname: Skarsgard
authors.forename: Kurian
authors.initials: K
authors.lastname: Joseph
authors.forename: Michael A
authors.initials: MA
authors.lastname: Sia
authors.forename: Robert G
authors.initials: RG
authors.lastname: Pearcey
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019583:Dose Fractionation, Radiation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D061089:Radiotherapy, Image-Guided; D016896:Treatment Outcome