PCPT Study: Expected Biases and Their Management

The PCPT trial aimed to compare prostate cancer incidence in men treated with finasteride versus placebo, addressing several methodological challenges to minimize bias. Finasteride's effect of reducing PSA levels by 50% required adjusting PSA thresholds to ensure equal biopsy rates between groups. The biopsy protocol was modified to focus on lateral peripheral cores due to reduced prostate volume. Patient adherence and contamination of the placebo group with finasteride were considered, as were biases from increased rectal exam sensitivity and prostate resections in the placebo group. The study concluded that systematic end-of-trial biopsies were the most reliable endpoint for assessing outcomes.