title: Minimal percentage of dose received by 90% of the urethra (%UD90) is the most significant predictor of PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer.
abstract: BACKGROUND
  To clarify the significant clinicopathological and postdosimetric parameters to predict PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy) for prostate cancer.
  
  
  METHODS
  We studied 200 consecutive patients who received LDR-brachytherapy between July 2004 and November 2008. Of them, 137 patients did not receive neoadjuvant or adjuvant androgen deprivation therapy. One hundred and forty-two patients were treated with LDR-brachytherapy alone, and 58 were treated with LDR-brachytherapy in combination with external beam radiation therapy. The cut-off value of PSA bounce was 0.1 ng/mL. The incidence, time, height, and duration of PSA bounce were investigated. Clinicopathological and postdosimetric parameters were evaluated to elucidate independent factors to predict PSA bounce in hormone-naïve patients who underwent LDR-brachytherapy alone.
  
  
  RESULTS
  Fifty patients (25%) showed PSA bounce and 10 patients (5%) showed PSA failure. The median time, height, and duration of PSA bounce were 17 months, 0.29 ng/mL, and 7.0 months, respectively. In 103 hormone-naïve patients treated with LDR-brachytherapy alone, and univariate Cox proportional regression hazard model indicated that age and minimal percentage of the dose received by 30% and 90% of the urethra were independent predictors of PSA bounce. With a multivariate Cox proportional regression hazard model, minimal percentage of the dose received by 90% of the urethra was the most significant parameter of PSA bounce.
  
  
  CONCLUSIONS
  Minimal percentage of the dose received by 90% of the urethra was the most significant predictor of PSA bounce in hormone-naïve patients treated with LDR-brachytherapy alone.
authors.affiliation: Department of Urology, Nara Medical University, Kashihara, Nara, Japan. sendo@naramed-u.ac.jp
authors.forename: Nobumichi
authors.initials: N
authors.lastname: Tanaka
authors.forename: Isao
authors.initials: I
authors.lastname: Asakawa
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Anai
authors.forename: Akihide
authors.initials: A
authors.lastname: Hirayama
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Noboru
authors.initials: N
authors.lastname: Konishi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hirao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000532:radiotherapy*; D011829:Radiation Dosage; D016896:Treatment Outcome; D014521:Urethra / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D017430:Prostate-Specific Antigen