Effect of prostate size on pathological outcome and biochemical recurrence after radical prostatectomy for prostate cancer: is it correlated with serum testosterone level?

Objective: To examine whether prostate size is associated with pathological outcome and biochemical recurrence (BCR) after radical prostatectomy (RP) in patients with prostate cancer, and to evaluate whether it is correlated with serum testosterone level.

Patients and methods: The study comprised 579 men treated with RP for prostate cancer between June 1991 and March 2008, with a prostate-specific antigen level of <20 ng/mL. We assessed the associations of prostate size (volume), measured using magnetic resonance imaging, and serum testosterone concentration, with adverse pathological outcomes and BCR.

Results: There was a positive correlation between preoperative prostate volume and prostate weight (r= 0.685, P < 0.001). On multivariate analysis, prostate volume was inversely associated with the outcomes of high-grade prostate cancer (P= 0.044), extracapsular extension (P= 0.011) and BCR (P= 0.016). There was also a positive correlation between serum testosterone level and prostate volume (r= 0.136, P= 0.043). Multivariate analysis showed that lower serum testosterone levels correlated with adverse pathological stage and a pathological Gleason score of ≥ 8 (P= 0.042). However, there was no relationship between serum testosterone level and BCR after adjusting for covariates.

Conclusions: Men with smaller prostates had unfavourable pathological findings and were at greater risk of progression after RP. Low serum testosterone levels were not associated with tumour progression. Therefore, another mechanism, aside from hormonal factors, might be involved in unfavourable outcomes in patients with a small prostate.