title: Clinical implications of a prostate-specific antigen bounce after radiation therapy for prostate cancer.
abstract: BACKGROUND
  The objectives are to determine predictors of a prostate-specific antigen (PSA) bounce, whether a PSA bounce after radiotherapy for prostate cancer is associated with biochemical disease-free survival (bDFS), and the time course to a PSA bounce versus a biochemical failure post-irradiation.
  
  
  METHODS
  Between July 2000 and December 2012, 691 prostate cancer patients without regional or distant metastases were treated with external beam radiation therapy and/or brachytherapy, and had at least 12 months of follow-up. A PSA bounce was defined as a temporary PSA increase of ≥ 0.4 ng/mL. bDFS was defined according to the nadir + 2 definition.
  
  
  RESULTS
  The median follow-up was 42 months. The median time to first PSA bounce was 17 months (95% confidence interval 15-18 months). In contrast, the median time to biochemical failure was 41 months (95% confidence interval 28-53 months). Two hundred and twenty-six of 691 (33%) patients had at least one PSA bounce with a median magnitude of 1.0 ng/mL (range 0.4-17.0). A Gleason score of 6 (p < 0.0001) predicted a PSA bounce on multivariate analysis. Patients with a PSA bounce experienced improved bDFS on multivariate analysis (p = 0.002).
  
  
  CONCLUSIONS
  Patients with a Gleason score of 6 were more likely to experience a PSA bounce which was associated with improved bDFS. A PSA bounce occurred sooner after radiotherapy than a biochemical failure. The authors recommend against performing prostate biopsies within 24-30 months of radiotherapy since an elevated PSA may simply represent a benign PSA bounce.
authors.affiliation: Department of Radiation Oncology, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL, 33612, USA.
authors.forename: Arash O
authors.initials: AO
authors.lastname: Naghavi
authors.forename: Tobin J
authors.initials: TJ
authors.lastname: Strom
authors.forename: Kevin
authors.initials: K
authors.lastname: Nethers
authors.forename: Alex A
authors.initials: AA
authors.lastname: Cruz
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Figura
authors.forename: Kushagra
authors.initials: K
authors.lastname: Shrinath
authors.forename: Binglin
authors.initials: B
authors.lastname: Yue
authors.forename: Jongphil
authors.initials: J
authors.lastname: Kim
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Biagioli
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Fernandez
authors.forename: Randy V
authors.initials: RV
authors.lastname: Heysek
authors.forename: Richard B
authors.initials: RB
authors.lastname: Wilder
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000532:radiotherapy*
chemical_list: D017430:Prostate-Specific Antigen