title: PSA response to neoadjuvant androgen deprivation is an independent prognostic marker and may identify patients who benefit from treatment escalation.
abstract: OBJECTIVE
  To determine whether prostate-specific antigen (PSA) measurement after initiation of androgen deprivation therapy (ADT) but prior to the start of radiotherapy (RT) pPSA is an independent predictor of biochemical relapse-free survival (bRFS). We also sought to determine the effect, if any, of factors affecting bRFS for patients who did not achieve pPSA<0.5 ng/mL.
  
  
  METHODS
  A total of 105 patients with National Comprehensive Cancer Network intermediate- or high-risk prostate cancer treated with neoadjuvant ADT (median = 3.9 mo) and external beam RT had pPSA data available and met the inclusion criteria. Pretreatment and treatment characteristics were included in a Cox proportional hazards model to determine effect on bRFS.
  
  
  RESULTS
  Median follow-up was 5.4 years. On multivariable analysis, pPSA≥0.5 ng/mL was associated with worsened bRFS (hazard ratio [HR] = 2.7, P = 0.013). For the subgroup of patients with at most 1 high-risk factor, pPSA remained a statistically significant prognostic factor. For patients within this subgroup who had pPSA≥0.5 ng/mL, the addition of pelvic RT was associated with a trend toward improved outcome (HR = 0.609, P = 0.083).
  
  
  CONCLUSIONS
  For patients with intermediate- or high-risk prostate cancer receiving neoadjuvant ADT, achieving pPSA<0.5 ng/mL was associated with improved rates of bRFS. Additionally, pPSA measurement may identify patients who may be able to benefit from escalated treatment such as pelvic RT.
authors.affiliation: Department of Radiation Oncology, University of Alabama, Birmingham, AL. Electronic address: ammcdonald@uabmc.edu.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: McDonald
authors.affiliation: Department of Radiation Oncology, University of Alabama, Birmingham, AL.
authors.forename: Rojymon
authors.initials: R
authors.lastname: Jacob
authors.affiliation: Department of Radiation Oncology, University of Alabama, Birmingham, AL.
authors.forename: Eddy S
authors.initials: ES
authors.lastname: Yang
authors.affiliation: Department of Radiation Oncology, University of Alabama, Birmingham, AL.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Dobelbower
authors.affiliation: Department of Radiation Oncology, University of Alabama, Birmingham, AL.
authors.forename: Sean
authors.initials: S
authors.lastname: Vanlandingham
authors.affiliation: Department of Radiation Oncology, University of Alabama, Birmingham, AL.
authors.forename: John B
authors.initials: JB
authors.lastname: Fiveash
mesh_terms: D000368:Aged; D000726:Androgen Antagonists / Q000627:therapeutic use*; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000532:radiotherapy; D016896:Treatment Outcome
chemical_list: D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen
keywords: Androgen deprivation; External beam radiation; PSA; PSA response to androgen deprivation; Pelvic radiation