title: Twenty-four-month postradiation prostate biopsies are strongly predictive of 7-year disease-free survival: results from a Canadian randomized trial.
abstract: BACKGROUND
  The objective of this study was to evaluate the predictive value of prostate biopsies that were obtained 24 months after the completion of radiotherapy (RT) with respect to disease-free survival (DFS) in a randomized trial that compared 3 months versus 8 months of neoadjuvant hormone therapy before conventional dose external RT.
  
  
  METHODS
  From February 1995 to June 2001, 378 men were randomized to receive either 3 months or 8 months of combined flutamide and goserelin before they received 66 Gray of RT at 4 participating centers. By risk group, 26% of patients were categorized as low risk, 43% were categorized as intermediate risk, and 31% were categorized as high risk. The 2 treatment arms were balanced in terms of age, Gleason score, clinical tumor classification, risk group, and presenting prostate-specific antigen level. The median follow-up for the patients who remained alive was 6.6 years (range, 1.6-10.1 years). Of 361 evaluable patients, 290 patients remained alive. Post-RT prostate biopsies were performed between 24 and 30 months after the completion of RT in 3 of the 4 centers. Biopsies that had residual tumor with severe treatment effect were considered indeterminate, and biopsies that had minimal or no treatment effect were considered positive.
  
  
  RESULTS
  The 5-year rate of actuarial freedom from any failure for the 3-month arm versus the 8-month arm was 72% versus 75% (P = .18). The DFS for patients who had negative and indeterminate biopsies was similar. Two-year post-treatment biopsy status was a strong predictor of 5-year DFS rate (82% and 83% for negative and indeterminate biopsies, respectively, vs 27% for positive biopsies; P < .0001). Multivariate analysis indicated that biopsy status (P < .0001) and Gleason score (P < .0001) were the strongest determinates of biochemical DFS.
  
  
  CONCLUSIONS
  Two-year post-RT prostate biopsies were strongly predictive of subsequent DFS. Biopsies with severe treatment effect were considered negative.
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada. juanita.crook@rmp.uhn.on.ca
authors.forename: Juanita M
authors.initials: JM
authors.lastname: Crook
authors.forename: Shawn
authors.initials: S
authors.lastname: Malone
authors.forename: Gad
authors.initials: G
authors.lastname: Perry
authors.forename: Libni
authors.initials: L
authors.lastname: Eapen
authors.forename: Julie
authors.initials: J
authors.lastname: Owen
authors.forename: Susan
authors.initials: S
authors.lastname: Robertson
authors.forename: Charles
authors.initials: C
authors.lastname: Ludgate
authors.forename: Sharon
authors.initials: S
authors.lastname: Fung
authors.forename: Gina
authors.initials: G
authors.lastname: Lockwood
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002170:Canada; D018572:Disease-Free Survival; D005485:Flutamide / Q000627:therapeutic use; D017273:Goserelin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D016896:Treatment Outcome
chemical_list: D017273:Goserelin; D005485:Flutamide