The influence of unscheduled biopsies on prostate cancer detection in the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial

1504^ Background: REDUCE is an ongoing 4-year, international, randomized, placebo-controlled study investigating the effect of dutasteride on the incidence of biopsy-detectable prostate cancer (PCa). We assessed the influence of prostate specific antigen (PSA)-driven, unscheduled biopsies on PCa detection. Methods: Eligible subjects were aged 50–75 years with serum PSA 2.5–10 ng/mL (50–60 years) or 3–10 ng/mL (>60 years) and a negative 6–12-core biopsy ≤6 months before enrollment. Protocol-mandated transrectal ultrasound directed biopsies (10 cores) were taken at 2 and 4 years; we report unblinded 2-year data. Results: Of the 8108 subjects in the efficacy population (subjects with no PCa in baseline biopsy as assessed by Central lab and who took at least one dose of study medication), 356 subjects (4.4%) underwent an unscheduled biopsy (0–18 months), and 6460 subjects (79.7%) underwent a protocol-mandated (scheduled) biopsy (19–24 months). Rising PSA was the primary reason for an unscheduled biopsy. PCa w...