Impact of Dutasteride on PSA Kinetics and Time to Progression in Men with PSA-only Recurrent Prostate Cancer

Background AVODART After Radical Therapy For Prostate Cancer Study (ARTS) reported dutasteride reduced PSA doubling (PSADT) at two years by 66% and disease progression by 59%. The durability of the cancer control is unknown. Objective Explore the impact of dutasteride on PSADT and time to progression in men with PSA-only recurrent disease. Design, Setting and Participants Retrospective examination of the impact of dutasteride on PSA kinetics and time to progression with PSA-only recurrent prostate cancer. Intervention Dutasteride daily. Outcome, Measurement and Statistical Analysis Change in PSA over time was determined by linear regression of natural log of PSA versus time. The slope of that curve was used as a measure of exponential PSA progression. Impact of dutasteride on slope was analyzed using Wilcoxon signed-rank two-sided test. Time to progression was analyzed using Kaplan-Meier, univariant and multivariant Cox regression. Results and Limitation Compared to men with BPH, patients showed little change in PSA during the first 3 months. Thereafter, the PSA resumed an exponential increase. PSADT was 10.3 months pre dutasteride and 24.8 months post dutasteride. Multivariant analysis showed a strong correlation between post dutasteride PSA kinetics and time to progression, with close to 50% relapse free at 10 years. Post-dutasteride, patients with PSADT >9 months had significantly better survival. Conclusions Dutasteride slows PSADT in PSA-only recurrent prostate cancer. This decline correlated with time to disease progression with close to 50% progression free at 10 years. Patient Summary Men with PSA-only recurrent prostate cancer on dutasteride experience a significant drop in the rate at which the PSA increases. If the PSA does not double between months 3-12, they are likely to remain free of metastases for many years.