title: Delayed radiotherapy for patients with localized prostate cancer: validation by propensity score matching.
abstract: OBJECTIVE
  To retrospectively investigate the biochemical outcome following delayed radiotherapy in patients with prostate cancer.
  
  
  METHODS
  From July 2000 to November 2008, 144 consecutive patients with localized prostate cancer underwent radiotherapy and androgen-deprivation therapy. Biochemical progression-free survival was compared in patients who began radiotherapy >6 months (delayed group) with these who began ≤ 6 months (non-delayed group) from diagnosis by biopsy. Treatment selection bias was adjusted by the propensity score method.
  
  
  RESULTS
  After a median follow-up of 64 months, the 5-year biochemical progression-free survival of the delayed and non-delayed groups was 87.4% (95% confidence interval, CI=69.7-95.1%) and 96.6% (95% CI=89.6-98.9%), respectively (p=0.03). Delayed radiotherapy was the only independent risk factor for biochemical progression (hazard ratio=3.97, 95% CI 1.07-14.7, p=0.04). The results were validated by propensity score analysis.
  
  
  CONCLUSIONS
  Delaying radiotherapy by >6 months increases the risk of biochemical progression in patients with localized prostate cancer.
authors.affiliation: Department of Radiation Oncology, Tsukuba Medical Center, Tsukuba, Ibaraki, Japan. hnakayam@tokyo-med.ac.jp
authors.forename: Hidetsugu
authors.initials: H
authors.lastname: Nakayama
authors.forename: Ayae
authors.initials: A
authors.lastname: Kanemoto
authors.forename: Koji
authors.initials: K
authors.lastname: Kikuchi
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Matsuki
authors.forename: Mitsuro
authors.initials: M
authors.lastname: Tomobe
authors.forename: Sadamu
authors.initials: S
authors.lastname: Tsukamoto
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Takeshima
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Oshiro
authors.forename: Shinji
authors.initials: S
authors.lastname: Sugahara
authors.forename: Koichi
authors.initials: K
authors.lastname: Tokuuye
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010043:Outcome and Process Assessment, Health Care / Q000706:statistics & numerical data*; D011379:Prognosis; D057216:Propensity Score; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors
chemical_list: D000726:Androgen Antagonists