Evaluating how much dutasteride actually reduces serum dihydrotestosterone level: A Reconsideration based on unexpected results from a study of treatment of benign prostatic hyperplasia with dutasteride

Abstract

Objective: This study aimed to evaluate the effect of dutasteride treatment of benign prostatic hyperplasia on serum steroidal sex hormones and prostate volume (PV). Methods: Thirty patients with benign prostate hyperplasia treated with dutasteride for one year were assessed for changes in PV and serum sex hormones (testosterone (T), dihydotestosterone (DHT), estradiol (E2) and dehydroepiandrosterone sulphate (DHEAS)). PV was measured by ultrasonography. A paired or unpaired t-test and Pearson’s correlation coefficient test were used for statistical analysis. Results: DHT and DHEAS decreased by 38.5% and 20.3%, respectively. On the contrary, T and E2 increased by 34.3% and 9.4%, respectively. PV and prostate-specific antigen decreased by 17.7% and 63.4%, respectively. The rate of decrease of DHT had a negative correlation with PV, and the rate of decrease of DHEAS had positive correlation with PV. Conclusion: DHT did not decrease as expected (previous studies showed a decrease of approximately 90%). However, DHEAS decreased more than a natural decrease. It is possible that the conversion from DHEAS to DHT, via the conversion to T, in the prostate was accelerated by the decrease of DHT, especially in larger prostates. However, this discrepancy cannot be full explained by the conversion from DHEAS to DHT, as mentioned above. Level of evidence: Level 2c