title: Impact of 5α-reductase inhibitors on men followed by active surveillance for prostate cancer.
abstract: BACKGROUND
  In two large randomized controlled trials, 5α-reductase inhibitors (5-ARIs) were shown to prevent prostate cancer. No prior work had shown the effect of 5-ARIs on those already diagnosed with low-risk prostate cancer.
  
  
  OBJECTIVE
  Our aim was to determine the effect of 5-ARIs on pathologic progression in men on active surveillance.
  
  
  METHODS
  We conducted a single-institution retrospective cohort study comparing men taking a 5-ARI versus no 5-ARI while on active surveillance for prostate cancer.
  
  
  METHODS
  Pathologic progression was evaluated and defined as Gleason score >6, maximum core involvement >50%, or more than three cores positive on a follow-up prostate biopsy. Kaplan-Meier analyses were conducted along with multivariable Cox proportional hazard regression modeling for predictors of pathologic progression.
  
  
  CONCLUSIONS
  A total of 288 men on active surveillance met the inclusion criteria. The median follow-up was 38.5 mo (interquartile range: 23.6-59.4) with 93 men (32%) experiencing pathologic progression and 96 men (33%) abandoning active surveillance. Men taking a 5-ARI experienced a lower rate of pathologic progression (18.6% vs 36.7%; p=0.004) and were less likely to abandon active surveillance (20% vs 37.6%; p=0.006). On multivariable Cox proportional hazards analysis, lack of 5-ARI use was most strongly associated with pathologic progression (hazard ratio: 2.91; 95% confidence interval, 1.5-5.6). The main study limitation was the retrospective design and variable duration of 5-ARI therapy.
  
  
  CONCLUSIONS
  The 5-ARIs were associated with a significantly lower rate of pathologic progression and abandonment of active surveillance.
authors.affiliation: Princess Margaret Hospital, University Health Network, University of Toronto, Ontario, Canada. antonio.finelli@uhn.on.ca
authors.forename: Antonio
authors.initials: A
authors.lastname: Finelli
authors.forename: Greg
authors.initials: G
authors.lastname: Trottier
authors.forename: Nathan
authors.initials: N
authors.lastname: Lawrentschuk
authors.forename: Robert
authors.initials: R
authors.lastname: Sowerby
authors.forename: Alexandre R
authors.initials: AR
authors.lastname: Zlotta
authors.forename: Lenny
authors.initials: L
authors.lastname: Radomski
authors.forename: Narhari
authors.initials: N
authors.lastname: Timilshina
authors.forename: Andrew
authors.initials: A
authors.lastname: Evans
authors.forename: Theodorus H
authors.initials: TH
authors.lastname: van der Kwast
authors.forename: Ants
authors.initials: A
authors.lastname: Toi
authors.forename: Micheal A S
authors.initials: MA
authors.lastname: Jewett
authors.forename: John
authors.initials: J
authors.lastname: Trachtenberg
authors.forename: Neil E
authors.initials: NE
authors.lastname: Fleshner
mesh_terms: D000368:Aged; D042944:Cholestenone 5 alpha-Reductase / Q000037:antagonists & inhibitors*; D016208:Databases, Factual; D018450:Disease Progression; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D016016:Proportional Hazards Models; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control*; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D004791:Enzyme Inhibitors; D042944:Cholestenone 5 alpha-Reductase