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AUA 2017

AUA 2017: Prostatic Tissue Androgen Levels as Prognostic Factor for Men with Metastatic Castration-resistant Prostate Cancer

Boston, MA (UroToday.com) The authors of this abstract presented at AUA 2017 expanded on previous work published by the same group with regard to tissue concentrations of testosterone (T) and dihydrotestosterone (DHT) in prostate biopsies from patients with known prostate cancer. Earlier, they found that men with higher T/DHT ratios within their prostate biopsies were likely to progress quicker to castration-resistance (CRPC) than men with lower T/DHT ratios in the specimen.

In this study, the authors aimed to evaluate if T/DHT levels may predict survival outcomes in CRPC patients. They analyzed 34 consecutive patients with already diagnosed metastatic CRPC (mCRPC). After progressing to CRPC status, these men had repeat prostate biopsies and the T and DHT levels in the specimens were measured using known techniques with mass spectrometry. In their analysis, they also controlled for other clinically relevant variables such as PSA, time to CRPC, and previous exposure to docetaxel or antiandrogens.

In their multivariate analysis, they found that, as one might expect, time to CRPC predicted worse prostate cancer-specific survival (time to CRPC<14 months; HR7.1, 95%CI1.63-38.1, p=0.022). Intriguingly, they also found that higher T/DHT ratios also predicted worse disease-specific survival (T/DHT ratio>1.5; HR5.2, 95%CI1.1-23.6, p=0.035).

The study has some inherent drawbacks, as it analyzes a low sample size of patients and has a short median follow up duration of only 7.4 months. Nonetheless, they did find that T/DHT levels were significant predictors of survival, even with the small sample they analyzed and with short follow-up.

The molecular mechanism behind the finding that higher T/DHT ratios exists in aggressive prostate cancer makes sense. Testosterone is converted to DHT in normal prostatic tissue, and aggressive malignancies, especially those that have progressed to castration-resistance, will have deletions or aberrations in the normal pathway converting T to DHT.

T/DHT ratios in prostate biopsy specimens appear to be a readily measureable and easily reproducible means for following men with advanced prostate cancer. More validation and study is needed, but this may be a simple and important tool that Urologists and Oncologists can use in actual clinical practice.

Authors: Yasuhide Miyoshi, Takashi Kawahara, Mari Ohtaka, Sohgo Tsutsumi, Koichi Uemura, Masato Yasui, Shuko Yoneyama, Yumiko Yokomizo, Narihiko Hayashi, Hiroji Uemura

Written By: Shreyas Joshi, MD, Fox Chase Cancer Center, Philadelphia, PA

at the 2017 AUA Annual Meeting - May 12 - 16, 2017 – Boston, Massachusetts, USA