title: Stereotactic body radiotherapy for low-risk prostate cancer: five-year outcomes.
abstract: OBJECTIVE
  Hypofractionated, stereotactic body radiotherapy (SBRT) is an emerging treatment approach for prostate cancer. We present the outcomes for low-risk prostate cancer patients with a median follow-up of 5 years after SBRT.
  
  
  METHODS
  Between Dec. 2003 and Dec. 2005, a pooled cohort of 41 consecutive patients from Stanford, CA and Naples, FL received SBRT with CyberKnife for clinically localized, low-risk prostate cancer. Prescribed dose was 35-36.25 Gy in five fractions. No patient received hormone therapy. Kaplan-Meier biochemical progression-free survival (defined using the Phoenix method) and RTOG toxicity outcomes were assessed.
  
  
  RESULTS
  At a median follow-up of 5 years, the biochemical progression-free survival was 93% (95% CI = 84.7% to 100%). Acute side effects resolved within 1-3 months of treatment completion. There were no grade 4 toxicities. No late grade 3 rectal toxicity occurred, and only one late grade 3 genitourinary toxicity occurred following repeated urologic instrumentation.
  
  
  CONCLUSIONS
  Five-year results of SBRT for localized prostate cancer demonstrate the efficacy and safety of shorter courses of high dose per fraction radiation delivered with SBRT technique. Ongoing clinical trials are underway to further explore this treatment approach.
authors.affiliation: Naples Radiation Oncology, PA, USA. dfreeman_md@yahoo.com
authors.forename: Debra E
authors.initials: DE
authors.lastname: Freeman
authors.forename: Christopher R
authors.initials: CR
authors.lastname: King
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000032:analysis / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology / Q000209:etiology; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods; D012306:Risk; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D017430:Prostate-Specific Antigen