title: Population-based validation of a policy change to use long-term androgen deprivation therapy for cT3-4 prostate cancer: impact of the EORTC22863 and RTOG 85-31 and 92-02 trials.
abstract: OBJECTIVE
  After publication of EORTC-22863 trial, prolonged androgen deprivation therapy (ADT) combined with radiation therapy (RT) became standard policy for high-risk prostate cancer patients in British Columbia (BC) in 1997. We evaluated whether population-based survival improved after this policy change.
  
  
  METHODS
  Two cohorts comprising all patients with T3-T4 prostate cancer treated with curative-intent RT in BC were reviewed. The Early cohort (n=730) was all patients treated between 1993 and 1995, and the Late cohort (n=584) was all patients treated between 1999 and 2001. The BC Cancer Registry, which collects data on survival, was linked to RT and pharmacy databases. Duration of ADT, age, stage, grade, presenting PSA, and Charlson comorbidity index (CCI; none=0, minor=1, major=2+), were abstracted from charts.
  
  
  RESULTS
  Usage of ≥6 months and ≥18 months of neoadjuvant and adjuvant ADT increased from 14% and 1% to 97% and 59% (p<0.0001). Baseline characteristics were similar, except for lower Gleason score (G2-6: 45% vs. 20%, G7: 35% vs. 48%, G8-10: 19% vs. 32%; p<0.0001), higher T-stage (T4: 9% vs. 5%, p=0.004) and higher comorbidity (CCI 0: 62% vs. 71%, CCI 1: 26% vs. 20%, CCI 2+: 11% vs. 9%, p=0.002) in the Early cohort. Disease-specific survival adjusted for competing risks from other causes mortality was improved (90% vs. 86%, p=0.042). On multivariate analysis, the Late cohort was independently associated with improved 8-year overall survival (76% vs. 64%, p=0.0002).
  
  
  CONCLUSIONS
  This population-based study demonstrated improved overall survival following a policy change to use of prolonged ADT with curative RT for patients with T3-T4 prostate cancer.
authors.affiliation: Radiation Therapy Program, BC Cancer Agency and University of BC, Vancouver, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Tran
authors.forename: Matthew
authors.initials: M
authors.lastname: Paquette
authors.forename: Tom
authors.initials: T
authors.lastname: Pickles
authors.forename: Justin
authors.initials: J
authors.lastname: Jay
authors.forename: Jeremy
authors.initials: J
authors.lastname: Hamm
authors.forename: Mitchell
authors.initials: M
authors.lastname: Liu
authors.forename: Jan
authors.initials: J
authors.lastname: Lim
authors.forename: Mira
authors.initials: M
authors.lastname: Keyes
authors.forename: Winkle
authors.initials: W
authors.lastname: Kwan
authors.forename: Scott
authors.initials: S
authors.lastname: Tyldesley
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D015331:Cohort Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D012189:Retrospective Studies
chemical_list: D000726:Androgen Antagonists
keywords: Androgen deprivation therapy; Overall survival; Prostate cancer; Radiation therapy; Validation study