title: End-of-radiation PSA as a novel prognostic factor in patients undergoing definitive radiation and androgen deprivation therapy for prostate cancer.
abstract: In men undergoing definitive radiation for prostate cancer, it is unclear whether early biochemical response can provide additional prognostic value beyond pre-treatment risk stratification.
  
  
  
  Prostate cancer patients consecutively treated with definitive radiation at our institution by a single provider from 1993 to 2006 and who had an end-of-radiation (EOR) PSA (n=688, median follow-up 11.2 years). We analyzed the association of an EOR PSA level, obtained during the last week of radiation, with survival outcomes. Multivariable-adjusted cox proportional hazards models were constructed to assess associations between a detectable EOR PSA (defined as ⩾0.1 ng ml-1) and biochemical failure-free survival (BFFS), metastasis-free survival (MFS), prostate cancer-specific survival (PCSS) and overall survival (OS). Kaplan-Meier survival curves were constructed, with stratification by EOR PSA.
  
  
  
  At the end of radiation, the PSA level was undetectable in 30% of patients. Men with a detectable EOR PSA experienced inferior 10-year BFFS (49.7% versus 64.4%, P<0.001), 10-year MFS (84.8% versus 92.0%, P=0.003), 10-year PCSS (94.3% versus 98.2%, P=0.007) and 10-year OS (75.8% versus 82.5%, P=0.01), as compared to men with an undetectable EOR PSA. Among National Comprehensive Care Network (NCCN) intermediate- and high-risk men who were treated with definitive radiation and androgen deprivation therapy (ADT), a detectable EOR PSA was more strongly associated with PCSS than initial NCCN risk level (EOR PSA: HR 5.89, 95% CI 2.37-14.65, P<0.001; NCCN risk level: HR 2.01, 95% CI 0.74-5.42, P=0.168). Main study limitations are retrospective study design and associated biases.
  
  
  
  EOR PSA was significantly associated with survival endpoints in men who received treatment with definitive radiation and ADT. Whether the EOR PSA can be used to modulate treatment intensity merits further investigation.
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: A K
authors.initials: AK
authors.lastname: Narang
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: J
authors.initials: J
authors.lastname: Trieu
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: N
authors.initials: N
authors.lastname: Radwan
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: A
authors.initials: A
authors.lastname: Ram
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Robertson
authors.affiliation: Department of Biostatistics, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: P
authors.initials: P
authors.lastname: He
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: C
authors.initials: C
authors.lastname: Gergis
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: E
authors.initials: E
authors.lastname: Griffith
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: H
authors.initials: H
authors.lastname: Singh
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: DeWeese
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: S
authors.initials: S
authors.lastname: Honig
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: A
authors.initials: A
authors.lastname: Annadanam
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: S
authors.initials: S
authors.lastname: Greco
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: C
authors.initials: C
authors.lastname: DeVille
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: T
authors.initials: T
authors.lastname: McNutt
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Departments of Oncology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: DeWeese
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Departments of Oncology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: D Y
authors.initials: DY
authors.lastname: Song
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Departments of Oncology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: P T
authors.initials: PT
authors.lastname: Tran
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000008:administration & dosage; D018572:Disease-Free Survival; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood* / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage
chemical_list: D000726:Androgen Antagonists; D017430:Prostate-Specific Antigen