title: Prostate-specific antigen decline during salvage radiation therapy following prostatectomy is associated with reduced biochemical failure.
abstract: OBJECTIVE
  To evaluate the prognostic value of prostate-specific antigen (PSA) decline during salvage radiation therapy (SRT) after prostatectomy.
  
  
  METHODS
  We reviewed an institutional database and identified all prostate cancer patients who were treated with SRT between the years 2003 and 2010, had at least 1 PSA measurement during their SRT course, and had no history of androgen deprivation therapy use prior to or during SRT. Disease characteristics, treatment information, and clinical outcomes data were tabulated for each patient. The PSA response during SRT was defined as a PSA decline of at least 0.2 ng/mL compared with the pretreatment PSA level. Bivariate and multivariate analyses using Cox proportional hazards modeling were performed to identify predictors of biochemical recurrence.
  
  
  RESULTS
  Sixty-four patients met eligibility criteria for this analysis. Median PSA before SRT was 0.63 ng/mL (interquartile range: 0.42-1.00). With a median follow-up time of 70 months after SRT, 5-year actuarial rates for biochemical control and metastasis-free survival were 61% (95% confidence interval [CI], 48%-75%) and 88% (95% CI, 79%-97%), respectively. The median number of PSA measurements per patient during SRT was 3 (range, 1-5). On bivariate analysis, PSA response during SRT and positive surgical margins were significantly associated with a decreased risk of biochemical recurrence (BR), with hazard ratios of 0.160 (95% CI, 0.059-0.431, P < .001) and 0.396 (95% CI, 0.168-0.935, P = .035). On multivariate analysis, PSA response during SRT and positive surgical margin were independent, favorable predictors for BR, with hazard ratios of 0.171 (95% CI, 0.063-0.463, P < .001) and 0.411 (95% CI, 0.177-0.956, P = .039). The 5-year biochemical control rate for PSA responders was 81%, compared with 37% for nonresponders (P < .001).
  
  
  CONCLUSIONS
  Prostate-specific antigen decline during SRT may be a valuable prognostic factor for subsequent clinical outcomes. Future studies should investigate the value of monitoring PSA during SRT and how PSA response may be used to personalize therapy.
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Rafi
authors.initials: R
authors.lastname: Kabarriti
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Nitin
authors.initials: N
authors.lastname: Ohri
authors.affiliation: Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Raquibul
authors.initials: R
authors.lastname: Hannan
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Nima
authors.initials: N
authors.lastname: Tishbi
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Sujith
authors.initials: S
authors.lastname: Baliga
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: McGovern
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Waleed F
authors.initials: WF
authors.lastname: Mourad
authors.affiliation: Department of Urology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Reza
authors.initials: R
authors.lastname: Ghavamian
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Shalom
authors.initials: S
authors.lastname: Kalnicki
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Chandan
authors.initials: C
authors.lastname: Guha
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York. Electronic address: mgarg@montefiore.org.
authors.forename: Madhur K
authors.initials: MK
authors.lastname: Garg
mesh_terms: D006801:Humans; D007610:Kallikreins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000378:metabolism*; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000532:radiotherapy* / Q000601:surgery; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000379:methods*
chemical_list: C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen