title: A simple model predicts freedom from biochemical recurrence after low-dose rate prostate brachytherapy alone.
abstract: OBJECTIVE
  The objective of this study was to describe a simple model that predicts freedom from biochemical recurrence (FFBR) in men with prostate cancer after treatment with low-dose rate prostate brachytherapy (LDRPB) alone.
  
  
  METHODS
  One hundred thirty-two men were treated with LDRPB alone between September 1997 and April 2001. Sixty-four percent of men had low-risk disease (prostate-specific antigen [PSA] <10, Gleason <7, and T stage <T2b) and 36% had intermediate-risk disease (PSA > or =10, Gleason > or =7, or T stage T2b). The dosimetric quantifier D90 was calculated from a computed tomography scan performed 1 month after LDRPB. The percent positive biopsies (PPB) were determined for all patients. FFBR was estimated using the product limit method. All P values are 2-sided.
  
  
  RESULTS
  The median follow-up is 65 months. The median D90 is 138 Gy (range, 47-221 Gy). Fourteen men have developed evidence of biochemical relapse at a median of 27 months (range, 6-42 months). The 5-year FFBR rate for the entire cohort is 88%. On univariate analysis, variables found to be associated with FFBR included: PSA, Gleason score, T stage, risk group, PPB, and D90. Multivariate analysis indicated that D90, PPB, and risk group were independently associated with FFBR. Patients were categorized based on the following 3 adverse prognostic factors: D90 <140 Gy, PPB > or =50%, and intermediate-risk group. Group 1 (0 factors, n = 30), group 2 (1 factor, n = 72), and group 3 (> or =2 factors, n = 30) patients had 5-year FFBR rates of 100% (+/-0%), 92% (+/-6%), and 67% (+/-18%) (P < 0.0001).
  
  
  CONCLUSIONS
  We have developed a simple, robust model based on implant quality and disease factors that predicts FFBR in men with prostate cancer treated with LDRPB alone.
authors.affiliation: Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Papagikos
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Rossi
authors.forename: James J
authors.initials: JJ
authors.lastname: Urbanic
authors.forename: Allan F
authors.initials: AF
authors.lastname: deGuzman
authors.forename: David L
authors.initials: DL
authors.lastname: McCullough
authors.forename: Peter E
authors.initials: PE
authors.lastname: Clark
authors.forename: W Robert
authors.initials: WR
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001706:Biopsy; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012008:Recurrence
chemical_list: D017430:Prostate-Specific Antigen