Baseline serum prostate specific antigen (PSA) levels predict degree of symptom improvement following therapy of benign prostatic hyperplasia (BPH) with finasteride

Finasteride aims at improving lower urinary symptoms associated with benign prostatic hyperplasia. It decreases prostate volume by 20-30%. There is a modest correlation between serum prostate specific antigen (PSA) and prostate volume in men with BPH. This analysis aims to study whether pretreatment PSA levels might predict the degree of symptom improvement in men with BPH treated with finasteride. Seven randomized clinical trials have compared one year of 5 mg finasteride and placebo for the treatment of clinical benign prostatic hyperplasia (BPH). The findings of the 4491 men participating in these trials provide an opportunity to investigate the heterogeneity of the effects seen in the individual studies and to identify pretreatment predictors of clinical outcomes as expressed by changes in prostate volume, prostate specific antigen (PSA), symptoms, and peak urinary flow rates. A formal meta-analysis using an Empirical Bayes approach employed data from all finasteride Phase III trials in North America and Internationally, the PROSPECT, SCAPR, Early Intervention, VA COOP, and the PROWESS trials. A pooled analysis was also undertaken on the combined dataset There were consistent effects across all seven trials for finasteride and improvements in symptoms, flow rates, and prostate volumes were similar among men with similar prostate volumes at baseline. Improvements were more pronounced in men with larger prostates. PSA baseline data were available in five studies. The between-treatment quasi IPSS symptom score improvement depends significantly on the baseline PSA level (p<0.05) with the largest improvements seen in men with the highest PSA levels. Peak flow rate improvements do not appear to depend on baseline PSA, however. PSA levels decrease significantly in men treated with finasteride with the effect being greater in men with the largest baseline prostate volume. Baseline prostate volume is a key predictor of response in the treatment of men with BPH with finasteride, and baseline PSA levels determine the magnitude of the symptom response.