Preliminary evaluation of the effect of dutasteride on PCA3 in post-DRE urine sediments: a randomized, open-label, parallel-group pilot study.

BACKGROUND: Dutasteride is commonly used in patients that are also at risk for prostate cancer (PCa). Therefore, the influence of dutasteride on PCa markers has to be studied. To date, only the effect of dutasteride on serum prostate-specific antigen (PSA) has been studied. This was the first study to investigate the effect of dutasteride on the new PCa marker PCA3, longitudinally and in a dose dependent manner. METHODS: From April 25, 2005 to October 31, 2006, 16 subjects with benign prostatic hyperplasia (BPH) and 9 subjects with clinically localized PCa were enrolled at the urological outpatient clinics of one university hospital and one community hospital. Eight subjects with BPH and five with PCa received 0.5 mg dutasteride once daily for 3 months, eight with BPH and four with PCa received 3.5 mg. No subjects were withdrawn because of adverse effects. RESULTS: In all four groups both 0.5 and 3.5 mg dutasteride had a variable effect on the PCA3 score. In contrast, its other effects were consistent as it rapidly reduced serum DHT by >or=90%, over time increased serum T by 20-30%, over time halved serum PSA and decreased prostate volume by 10-16%. CONCLUSIONS: In this exploratory/pilot study the effect of dutasteride on the PCA3 score was variable. This should be taken into account while using PCA3 in diagnostics. As this study was exploratory, the influence of androgen-deprivation therapy on the PCA3 score should be analyzed further.