title: Kinetics differences between PSA bounce and biochemical failure in patients treated with 125I prostate brachytherapy.
abstract: OBJECTIVE
  To determine the helpful factors to distinguish prostate-specific antigen failure from prostate-specific antigen bounce with large magnitude.
  
  
  METHODS
  From October 2004 to December 2009, 242 patients with prostate cancer treated with (125)I brachytherapy were analyzed, 88 patients were excluded because the follow-up durations were shorter than 5 years. Their median follow-up was 80.4 months (60.0-123.9). Prostate-specific antigen failure was determined using the Phoenix definition. Prostate-specific antigen bounce was defined as an increase ≥0.2 ng/ml above the nadir, followed by a spontaneous return to the nadir. Prostate-specific antigen bounce +2 was defined as a prostate-specific antigen rise by 2.0 ng/ml or more above the nadir.
  
  
  RESULTS
  The 5-year biochemical relapse-free survival rate was 90.2%. Prostate-specific antigen failure and prostate-specific antigen bounce +2 were seen in 23 patients (14.9%) and 12 patients (7.8%), respectively. On univariate analysis, age at implant (P = 0.028), T stage (P = 0.020), time to prostate-specific antigen failure or prostate-specific antigen bounce (time to onset) (P = 0.0008), prostate-specific antigen velocity (P = 0.0003) and prostate-specific antigen doubling time (P = 0.0004) were significant for the distinction between prostate-specific antigen failure and prostate-specific antigen bounce +2. On multivariate analysis, no factor was the statistically significant factor. On receiver operating characteristic curve analysis, time to onset with a cutoff value of 29.8 months, prostate-specific antigen velocity of 0.18 ng/ml/month and prostate-specific antigen doubling time of 6.3 months had the highest accuracy of 82.9, 82.9 and 82.9% for prostate-specific antigen failure, respectively.
  
  
  CONCLUSIONS
  Time to onset, prostate-specific antigen velocity and prostate-specific antigen doubling time would be helpful for distinction between prostate-specific antigen failure and prostate-specific antigen bounce +2.
authors.affiliation: Department of Radiation Oncology, Shikoku Cancer Center Hospital, National Hospital Organization, Matsuyama hikanzaki@shikoku-cc.go.jp.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kanzaki
authors.affiliation: Department of Radiation Oncology, Shikoku Cancer Center Hospital, National Hospital Organization, Matsuyama.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kataoka
authors.affiliation: Department of Radiation Oncology, Shikoku Cancer Center Hospital, National Hospital Organization, Matsuyama.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nishikawa
authors.affiliation: Department of Radiation Oncology, Shikoku Cancer Center Hospital, National Hospital Organization, Matsuyama.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Uwatsu
authors.affiliation: Department of Radiation Oncology, Shikoku Cancer Center Hospital, National Hospital Organization, Matsuyama.
authors.forename: Kei
authors.initials: K
authors.lastname: Nagasaki
authors.affiliation: Department of Radiation Oncology, Shikoku Cancer Center Hospital, National Hospital Organization, Matsuyama.
authors.forename: Noriko
authors.initials: N
authors.lastname: Nishijima
authors.affiliation: Department of Urology, Shikoku Cancer Center Hospital, National Hospital Organization, Matsuyama, Japan.
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Hashine
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D001918:Brachytherapy; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D053208:Kaplan-Meier Estimate; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000532:radiotherapy*; D012372:ROC Curve; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D017430:Prostate-Specific Antigen
keywords: 125I seed; brachytherapy; prostate cancer; prostate-specific antigen