title: Concurrent androgen deprivation therapy during salvage prostate radiotherapy improves treatment outcomes in high-risk patients.
abstract: OBJECTIVE
  To determine whether concurrent androgen deprivation therapy (ADT) during salvage radiotherapy (RT) improves prostate cancer treatment outcomes.
  
  
  METHODS
  A total of 630 postprostatectomy patients were retrospectively identified who were treated with three-dimensional conformal RT. Of these, 441 were found to be treated for salvage indications. Biochemical failure was defined as prostate-specific antigen (PSA) of 0.2 ng/mL or greater above nadir with another PSA increase or the initiation of salvage ADT. Progression-free survival (PFS) was defined as the absence of biochemical failure, continued PSA rise despite salvage therapy, initiation of systemic therapy, clinical progression, or distant failure. Multivariate-adjusted Cox proportional hazards modeling was performed to determine which factors predict PFS.
  
  
  RESULTS
  Low-, intermediate-, and high-risk patients made up 10%, 24%, and 66% of patients, respectively. The mean RT dose was 68 Gy. Twenty-four percent of patients received concurrent ADT (cADT). Regional pelvic nodes were treated in 16% of patients. With a median follow-up of 3 years, the 3-year PFS was 4.0 years for cADT vs. 3.4 years for cADT patients (p = 0.22). Multivariate analysis showed that concurrent ADT (p = 0.05), Gleason score (p < 0.001), and pre-RT PSA (p = 0.03) were independent predictors of PFS. When patients were stratified by risk group, the benefits of cADT (hazard ratio, 0.65; p = 0.046) were significant only for high-risk patients.
  
  
  CONCLUSIONS
  This retrospective study showed a PFS benefit of concurrent ADT during salvage prostate RT. This benefit was observed only in high-risk patients.
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Soto
authors.forename: Michael N
authors.initials: MN
authors.lastname: Passarelli
authors.forename: Stephanie
authors.initials: S
authors.lastname: Daignault
authors.forename: Howard M
authors.initials: HM
authors.lastname: Sandler
mesh_terms: D000726:Androgen Antagonists / Q000627:therapeutic use*; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D020266:Radiotherapy, Conformal; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen