The effect of finasteride on prostate specific antigen: Review of available data

Purpose: We reviewed the available data on the effect of finasteride on serum levels of prostate specific antigen (PSA), PSA velocity and PSA density in men with benign prostatic hyperplasia (BPH) and prostate cancer. Materials and Methods: To our knowledge all previously published analyses of PSA data from clinical trials of finasteride therapy for BPH and prostate cancer are reviewed. Results: The normal reference range of serum PSA levels in men with BPH and no evidence of prostate cancer who were treated with finasteride for 6 months or longer is half that in untreated men with BPH. The percent by which serum levels of PSA are suppressed after 6 months of treatment for prostate cancer does not tend to be greater than that for BPH. Conclusions: To interpret serum PSA levels in men with BPH treated with finasteride for 6 months or longer, the serum PSA level should be multiplied by 2 and compared to either age-independent or age-specific upper limits of normal for serum PSA in untreated men with BPH. On the basis of limited data the sensitivity and specificity of this approach appear to be similar to those of the corresponding PSA limits in untreated men with BPH.