title: Opportunistic testing versus organized prostate-specific antigen screening: outcome after 18 years in the Göteborg randomized population-based prostate cancer screening trial.
abstract: BACKGROUND
  It has been shown that organized screening decreases prostate cancer (PC) mortality, but the effect of opportunistic screening is largely unknown.
  
  
  OBJECTIVE
  To compare the ability to reduce PC mortality and the risk of overdiagnosis between organized and opportunistic screening.
  
  
  METHODS
  The Göteborg screening study invited 10 000 randomly selected men for prostate-specific antigen (PSA) testing every 2 yr since 1995, with a prostate biopsy recommended for men with PSA ≥2.5 ng/ml. The control group of 10 000 men not invited has been exposed to a previously reported increased rate of opportunistic PSA testing. Both groups were followed until December 31, 2012.
  
  
  METHODS
  Observed cumulative PC incidence and mortality rates in both groups were calculated using the actuarial method. Using historical data from 1990-1994 (pre-PSA era), we calculated expected PC incidence and mortality rates in the absence of any PSA testing. The number needed to invite (NNI) and the number needed to diagnose (NND) were calculated by comparing the expected versus observed incidence and mortality rates.
  
  
  CONCLUSIONS
  At 18 yr, 1396 men were diagnosed with PC and 79 men died of PC in the screening group, compared to 962 and 122, respectively, in the control group. In the screening group, the observed cumulative PC incidence/mortality was 16%/0.98% compared to expected values of 6.8%/1.7%. The corresponding values for the control group were 11%/1.5% and 6.9%/1.7%. Organized screening was associated with an absolute PC-specific mortality reduction of 0.72% (95% confidence interval [CI] 0.50-0.94%) and relative risk reduction of 42% (95% CI 28-54%). There was an absolute reduction in PC deaths of 0.20% (95% CI -0.06% to 0.47%) and a relative risk reduction of 12% (95% CI -5 to 26%) associated with opportunistic PSA testing. NNI and NND were 139 (95% CI 107-200) and 13 for organized biennial screening and 493 (95% CI 213- -1563) and 23 for opportunistic screening. The extent of opportunistic screening could not be measured; incidence trends were used as a proxy.
  
  
  CONCLUSIONS
  Organized screening reduces PC mortality but is associated with overdiagnosis. Opportunistic PSA testing had little if any effect on PC mortality and resulted in more overdiagnosis, with almost twice the number of men needed to be diagnosed to save one man from dying from PC compared to men offered an organized biennial screening program.
  
  
  RESULTS
  Prostate-specific antigen (PSA) screening within the framework of an organized program seems more effective than unorganized screening.
authors.affiliation: Department of Urology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden. Electronic address: r.godtman@gmail.com.
authors.forename: Rebecka
authors.initials: R
authors.lastname: Arnsrud Godtman
authors.affiliation: Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Holmberg
authors.affiliation: Departments of Laboratory Medicine, Surgery (Urology), and Medicine (GU Oncology), Memorial Sloan-Kettering Cancer Center, New York, NY, USA; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK; Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden.
authors.forename: Hans
authors.initials: H
authors.lastname: Lilja
authors.affiliation: Department of Urology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Stranne
authors.affiliation: Department of Urology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Hugosson
mesh_terms: D000368:Aged; D001706:Biopsy; D055088:Early Detection of Cancer / Q000379:methods*; D006801:Humans; D015994:Incidence; D007610:Kallikreins / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D000069342:Medical Overuse / Q000706:statistics & numerical data; D008875:Middle Aged; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000401:mortality; D013548:Sweden / Q000453:epidemiology
chemical_list: C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
keywords: Opportunistic; Organized; Overdiagnosis; Prostate cancer; Prostate-specific antigen; Screening