title: Prostate-specific antigen bounce after high-dose-rate monotherapy for prostate cancer.
abstract: OBJECTIVE
  To characterize the magnitude and kinetics of prostate-specific antigen (PSA) bounces after high-dose-rate (HDR) monotherapy and determine relationships between certain clinical factors and PSA bounce.
  
  
  METHODS
  Longitudinal PSA data and various clinical parameters were examined in 157 consecutive patients treated with HDR monotherapy between 1996 and 2005. We used the following definition for PSA bounce: rise in PSA ≥threshold, after which it returns to the prior level or lower. Prostate-specific antigen failure was defined per the Phoenix definition (nadir +2 ng/mL).
  
  
  RESULTS
  A PSA bounce was noted in 67 patients (43%). The number of bounces per patient was 1 in 45 cases (67%), 2 in 19 (28%), 3 in 2 (3%), 4 in 0, and 5 in 1 (1%). The median time to maximum PSA bounce was 1.3 years, its median magnitude was 0.7, and its median duration was 0.75 years. Three patients (2%) were noted to have PSA failure. None of the 3 patients who experienced biochemical failure exhibited PSA bounce. In the fully adjusted model for predicting each bounce, patients aged <55 years had a statistically significant higher likelihood of experiencing a bounce (odds ratio 2.22, 95% confidence interval 1.38-3.57, P=.001). There was also a statistically significant higher probability of experiencing a bounce for every unit decrease in Gleason score (odds ratio 1.52, 95% confidence interval 1.01-2.04, P=.045).
  
  
  CONCLUSIONS
  A PSA bounce occurs in a significant percentage of patients treated with HDR monotherapy, with magnitudes varying from <1 in 28% of cases to ≥1 in 15%. The median duration of bounce is <1 year. More bounces were identified in patients with lower Gleason score and age <55 years. Further investigation using a model to correlate magnitude and frequency of bounces with clinical variables are under way.
authors.affiliation: University of California, Los Angeles, Los Angeles, California 90095, USA. nmehta@mednet.ucla.edu
authors.forename: Niraj H
authors.initials: NH
authors.lastname: Mehta
authors.forename: Mitchell
authors.initials: M
authors.lastname: Kamrava
authors.forename: Pin-Chieh
authors.initials: PC
authors.lastname: Wang
authors.forename: Michael
authors.initials: M
authors.lastname: Steinberg
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Demanes
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001918:Brachytherapy; D016001:Confidence Intervals; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D016017:Odds Ratio; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage
chemical_list: D017430:Prostate-Specific Antigen