The REDUCE Follow-Up Study: Low Rate of New Prostate Cancer Diagnoses Observed During a 2-Year, Observational, Followup Study of Men Who Participated in the REDUCE Trial

Purpose: The primary objective of the REDUCE (REduction by DUtasteride of prostate Cancer Events) Follow-Up Study was to collect data on the occurrence of newly diagnosed prostate cancers for 2 years beyond the 4-year REDUCE study. Materials and Methods: The 4-year REDUCE study evaluated prostate cancer risk reduction in men taking dutasteride. This 2-year observational study followed men from REDUCE with a clinic visit shortly after study conclusion and with up to 2 annual telephone calls during which patient reported data were collected regarding prostate cancer events, chronic medication use, prostate specific antigen levels and serious adverse events. No study drug was provided and all biopsies during the 2-year followup were performed for cause. The primary objective was to collect data on the occurrence of new biopsy detectable prostate cancers. Secondary end points included assessment of Gleason score and serious adverse events. Results: A total of 2,751 men enrolled in the followup study with numbers similar to those of the REDUCE former treatment groups (placebo and dutasteride). Few new prostate cancers were detected during the 2-year followup period in either former treatment group. A greater number of cancers were detected in the former dutasteride group than in the former placebo group (14 vs 7 cases). No Gleason score 8-10 prostate cancers were detected in either former treatment group based on central pathology review. No new safety issues were identified during the study. Conclusions: Two years of followup of the REDUCE study cohort demonstrated a low rate of new prostate cancer diagnoses in the former placebo and dutasteride treated groups. No new Gleason 8-10 cancers were detected.