The relationship between pre-radiation therapy testosterone levels and prostate cancer aggressiveness.

We investigated whether there is an association between testosterone levels and prostate cancer aggressiveness in patients treated with radiation therapy who underwent a prostatectomy or prostate radiotherapy (EBRT). A total of 380 patients who received primary or post-operative radiotherapy were identified. At the time of radiotherapy, baseline testosterone levels and body mass index (BMI) measurements were available. On multivariate analysis (MVA), higher prostate-specific antigen (PSA) levels were predictive of testosterone ≥10.4  (OR = 1.3, p = .04) and testosterone ≥12.0 nmol/L (OR = 1.3, p = .04). Patients with a Gleason score ≥8 were more likely to have testosterone <8 nmol/L than patients with a lower score (31% vs. 20%, p = .043). On univariate analysis, a Gleason score ≥8 was associated with a lower likelihood of having a normal (≥8 nmol/L) testosterone level (OR = 0.51, 95% CI: 0.3-0.9, p = .02), and on MVA adjusted for post-surgical versus primary EBRT and BMI (≥30 kg/m2 ), the Gleason score lost its statistical significance (p = .09). While higher PSA levels are associated with higher testosterone levels, the interaction between Gleason score and testosterone is unclear and merits further study.