title: A systematic review of the volume-outcome relationship for radical prostatectomy.
abstract: BACKGROUND
  Due to the complexity and challenging nature of radical prostatectomy (RP), it is likely that both short- and long-term outcomes strongly depend on the cumulative number of cases performed by the surgeon as well as by the hospital.
  
  
  OBJECTIVE
  To review systematically the association between hospital and surgeon volume and perioperative, oncologic, and functional outcomes after RP.
  
  
  METHODS
  A systematic review of the literature was performed, searching PubMed, Embase, and Scopus databases for original and review articles between January 1, 1995, and December 31, 2011. Inclusion and exclusion criteria comprised RP, hospital and/or surgeon volume reported as a predictor variable, a measurable end point, and a description of multiple hospitals or surgeons.
  
  
  RESULTS
  Overall 45 publications fulfilled the inclusion criteria, where most data originated from retrospective institutional or population-based cohorts. Studies generally focused on hospital or surgeon volume separately. Although most of these analyses corroborated the impact of increasing volume with better outcomes, some failed to find any significant effect. Studies also differed with respect to the proposed volume cut-off for improved outcomes, as well as the statistical means of evaluating the volume-outcome relationship. Five studies simultaneously compared hospital and surgeon volume, where results suggest that the importance of either hospital or surgeon volume largely depends on the end point of interest.
  
  
  CONCLUSIONS
  Undeniable evidence suggests that increasing volume improves outcomes. Although it would seem reasonable to refer RP patients to high-volume centers, such regionalization may not be entirely practical. As such, the implications of such a shift in practice have yet to be fully determined and warrant further exploration.
authors.affiliation: CRCHUM, Centre Hospitalier de l'Université de Montréal, Montreal, Canada; Cancer Prognostics and Health Outcomes Unit, Centre Hospitalier de l'Université de Montréal, Montreal, Canada; Vattikuti Urology Institute, Henry Ford Health System, Detroit, MI, USA. Electronic address: trinh.qd@gmail.com.
authors.forename: Quoc-Dien
authors.initials: QD
authors.lastname: Trinh
authors.forename: Anders
authors.initials: A
authors.lastname: Bjartell
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Freedland
authors.forename: Brent K
authors.initials: BK
authors.lastname: Hollenbeck
authors.forename: Jim C
authors.initials: JC
authors.lastname: Hu
authors.forename: Shahrokh F
authors.initials: SF
authors.lastname: Shariat
authors.forename: Maxine
authors.initials: M
authors.lastname: Sun
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Vickers
mesh_terms: D002983:Clinical Competence; D061847:Hospitals, High-Volume / Q000592:standards; D061846:Hospitals, Low-Volume / Q000592:standards; D006801:Humans; D008297:Male; D010043:Outcome and Process Assessment, Health Care / Q000592:standards; D011468:Prostatectomy / Q000009:adverse effects / Q000401:mortality / Q000592:standards; D019984:Quality Indicators, Health Care; D012017:Referral and Consultation; D013997:Time Factors; D016896:Treatment Outcome
keywords: Hospital volume; Prostatectomy; Prostatic neoplasms; Regionalization; Selective referral; Surgeon volume