title: Screening with prostate specific antigen and metastatic prostate cancer risk: a population based case-control study.
abstract: OBJECTIVE
  Screening of asymptomatic men with prostate specific antigen (PSA) remains a controversial issue. There is limited evidence that screening is effective in reducing mortality from prostate cancer. In the current study we determined if screening with PSA reduces the risk of metastatic prostate cancer.
  
  
  METHODS
  We conducted a population based case-control study among the residents of Metropolitan Toronto and 5 surrounding counties in Ontario, Canada. Data were obtained from 236 cases of metastatic prostate cancer and 462 controls randomly sampled from the source population and frequency matched to cases for age and area of residence. History of PSA testing, digital rectal examination, symptoms and other data were obtained from medical records and a self-administered questionnaire. The association between PSA screening and metastatic prostate cancer was measured by the Mantel-Haenszel odds ratio stratified by exposure observation time and other potential confounding factors.
  
  
  RESULTS
  In asymptomatic men, the frequency of PSA screening as determined from medical records was significantly lower among the cases compared with the controls (odds ratio 0.65, 95% confidence interval 0.45 to 0.93). The odds ratio was 0.52 (0.28 to 0.98) in men 45 to 59 years old and 0.67 (0.41 to 1.09) in those 60 to 84 years old.
  
  
  CONCLUSIONS
  In this case-control study screening of asymptomatic men with PSA was associated with a significantly reduced risk of metastatic prostate cancer. The results need to be confirmed in randomized controlled trials.
authors: Department of Health Care and Epidemiology, University of British Columbia, Vancouver, Canada. jkopec@arthritisresearch.ca
authors: Jacek A
authors: JA
authors: Kopec
authors: Vivek
authors: V
authors: Goel
authors: Peter S
authors: PS
authors: Bunting
authors: Jan
authors: J
authors: Neuman
authors: Eric C
authors: EC
authors: Sayre
authors: Padraig
authors: P
authors: Warde
authors: Peter
authors: P
authors: Levers
authors: Neil
authors: N
authors: Fleshner
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D008403:Mass Screening; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000473:pathology*; D018570:Risk Assessment
chemical_list: D017430:Prostate-Specific Antigen