Design of the Prostate Cancer Prevention Trial (PCPT)

Control Clin Trials. 1995 Jun;16(3):150-63. doi: 10.1016/0197-2456(94)00xxx-m.


The PCPT is a chemoprevention trial of finasteride with a primary endpoint of biopsy-proven presence or absence of prostate cancer. A total of 18,000 healthy men, aged 55 years and older, will be randomized. Half will receive finasteride (5 mg/day) and half will receive placebo (one matching tablet per day) for 7 years. The trial is designed to have 92% power to detect a 25% reduction in period prevalence of biopsy-proven disease using a two-sided test with alpha = 0.05. The trial is complicated by the known impact of finasteride on the major screening test for prostate cancer, prostate specific antigen (PSA). This paper describes the PCPT design with reference to alternatives that were considered. The chosen design depends on five critical assumptions that must be monitored closely throughout the 9-year trial.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Bias
  • Confounding Factors, Epidemiologic
  • Double-Blind Method
  • Finasteride / adverse effects
  • Finasteride / pharmacology
  • Finasteride / therapeutic use*
  • Humans
  • Male
  • Middle Aged
  • Prostate-Specific Antigen / drug effects*
  • Prostate-Specific Antigen / metabolism
  • Prostatic Neoplasms / prevention & control*
  • Random Allocation
  • Randomized Controlled Trials as Topic / methods*
  • Randomized Controlled Trials as Topic / standards
  • Reproducibility of Results
  • Research Design*
  • Sample Size
  • Sexual Dysfunction, Physiological / chemically induced
  • United States


  • Finasteride
  • Prostate-Specific Antigen