Impact of Pre-treatment Prostate Tissue Androgen Content on the Prediction of Castration-resistant Prostate Cancer Development in Patients Treated with Primary Androgen Deprivation Therapy

Great advances in tissue androgen analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) have made it possible to evaluate the tissue androgen content from a single needle prostate biopsy specimen. In this study, we investigated if pre-treatment androgen content in prostate biopsy specimens could predict their response to primary androgen deprivation therapy (ADT) and future castration-resistant prostate cancer (CRPC). One-hundred and sixty-five prostate cancer patients who received primary ADT were enrolled. They had received multiple core prostate needle biopsy at diagnosis, and an additional one needle biopsy specimen was obtained for tissue androgen determination using LC-MS/MS. The patients' prostate specific antigen (PSA) values were periodically followed during the treatment and patients were determined to have CRPC when their PSA value increased continuously to 25% above the nadir and a 2.0 ng/mL increase. A significant correlation was found between PSA value decline velocity (PSA half-time) after ADT and pre-ADT tissue androgen content. Twenty-three patients were determined to have CRPC. These CRPC patients had a significantly high concentration of tissue T (p < 0.01) and low concentration of tissue 5α-dihydrotestosterone (DHT) (p < 0.01), resulting in a higher tissue T/DHT ratio (p < 0.001). A multivariate Cox proportional hazard model revealed the pre-ADT tissue T/DHT ratio and Gleason score as independent predictors for CRPC development. By using the two statistically significant variables, the relative risk of CRPC development could be calculated. The results of this study suggest that the evaluation of prostate androgen content in a single needle biopsy specimen may be useful to predict future CRPC development after primary ADT. Further studies are required for the clinical application of T/DHT ratio evaluation.