title: Primary radiotherapy vs conservative management for localized prostate cancer--a population-based study.
abstract: BACKGROUND
  Radiotherapy is the most common curative cancer therapy used for elderly patients with localized prostate cancer. However, the effectiveness of this approach has not been established. The purpose of this study is to evaluate the long-term outcomes of primary radiotherapy compared with conservative management in order to facilitate treatment decisions.
  
  
  METHODS
  This population-based study consisted of 57,749 patients with T1-T2 prostate cancers diagnosed during 1992-2007. We utilized an instrumental variable (IV) analytical approach with competing risk models to evaluate the outcomes of primary radiotherapy vs conservative management. The IV was comprised of combined health service areas with high- and low-use areas corresponding to the top and bottom tertile in radiotherapy usage rates.
  
  
  RESULTS
  In patients with low-/intermediate-risk prostate cancer, 10-year prostate cancer-specific and overall survival was similar in high- and low-radiotherapy use areas (96.1 vs 95.4% and 56.6 vs 56.3%, respectively). In patients with high-risk disease, however, areas with high-radiotherapy use had a higher 10-year cancer-specific survival (90.2 vs 88.1%, difference 2.1%; 95% CI 0.3-4.0%) and 10-year overall survival (53.3 vs 50.2%, difference 3.1%; 95% CI 1.3-6.3%). Results were similar irrespective of the type of radiotherapy used. To assess the robustness of our choice of IV, we repeated the IV analytical approach using different IVs (using the median utilization rate as the cutoff) and found the results to be similar.
  
  
  CONCLUSIONS
  Among men >65 years of age, the benefit of primary radiotherapy for localized disease is largely confined to patients with high-risk prostate cancer (Gleason scores 7-10).
authors.affiliation: Department of Medicine, Rutgers, Robert Wood Johnson Medical School, Piscataway, NJ, USA.|Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Lu-Yao
authors.affiliation: Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.|Department of Radiation Oncology, Rutgers, Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.affiliation: Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.|Department of Biostatistics, Rutgers, School of Public Health, Piscataway, NJ, USA.
authors.forename: D F
authors.initials: DF
authors.lastname: Moore
authors.affiliation: Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.|Department of Biostatistics, Rutgers, School of Public Health, Piscataway, NJ, USA.
authors.forename: W
authors.initials: W
authors.lastname: Shih
authors.affiliation: Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.|Department of Biostatistics, Rutgers, School of Public Health, Piscataway, NJ, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Medicine, Rutgers, Robert Wood Johnson Medical School, Piscataway, NJ, USA.|Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: DiPaola
authors.affiliation: Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.
authors.forename: S
authors.initials: S
authors.lastname: Shen
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Zietman
authors.affiliation: Department of Medicine, Rutgers, Robert Wood Johnson Medical School, Piscataway, NJ, USA.|Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.
authors.forename: S-L
authors.initials: SL
authors.lastname: Yao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D003131:Combined Modality Therapy; D015897:Comorbidity; D019468:Disease Management; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011159:Population Surveillance; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology* / Q000628:therapy*; D011878:Radiotherapy / Q000379:methods; D018426:SEER Program; D016019:Survival Analysis; D016896:Treatment Outcome