Login to Access Video or Poster Abstract: MP53-03
Sources of Funding: None

Introduction

We investigated whether lower testosterone threshold compared to traditionally accepted level of castrate-level testosterone (< 50 ng/dl) has an impact on time to progression to castrate-resistant prostate cancer (CRPC) in patients undergoing continuous androgen deprivation therapy (ADT).

Methods

A single-center, prospective review of 153 consecutive patients undergoing ADT from 2006 to 2016 was performed. Patients were excluded from the analysis if they received intermittent ADT, concurrent ADT with external beam radiation therapy, or if they did not achieve castrate-level testosterone (< 50 ng/dl). Serum testosterone was measured every three months after initiation of ADT. Patients were categorized based on their 1-year mean testosterone value (< 20 ng/dl, 20-32 ng/dl, 32-50 ng/dl, > 50 ng/dl) and outcome measures were compared. Progression to CRPC was assessed with the Kaplan-Meier method. Statistical analysis was performed using the log-rank, Breslow, and Tarone-Ware tests to compare the groups.

Results

A total of 112 patients were included in the analysis. Median age at diagnosis was 67.9 (range: 50.9-89.1). Median follow-up was 27.9 months (range: 3.3-114.6). Median PSA prior to initiation of ADT was 18 ng/mL (range: 0.61-2940). 72.3% of patients achieved a 1-year mean T < 20 ng/dl; 18.6% achieved 20-32 ng/dl; 5.4% achieved 32-50 ng/dl; and 3.6% achieved > 50 ng/dl. There was no statistically significant difference in progression-free survival between patients with different levels of 1-year mean testosterone values (log-rank p=0.813).

Conclusions

The results suggest that there may not be a significant impact of strict testosterone control beyond what is considered the traditional castrate-level testosterone. However, only a small proportion of patients had 1-year testosterone > 32 ng/dl (9.0%). A larger study may reveal a beneficial role of strict testosterone reduction in the management of advanced prostate cancer.

Funding

None