1. ¹Department of Urology, Graduate School of Medicine, Chiba University, Chiba, Japan
2. ²Department of Pathology, Faculty of Medicine, Mie University, Mie, Japan

Correspondence: Dr T Imamoto, Department of Urology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. E-mail: t-imamo@pg7.so-net.ne.jp

Received 26 March 2008; Revised 6 May 2008; Accepted 12 May 2008; Published online 3 June 2008.

Abstract

The relationships between serum level of testosterone (T) and prostate cancer (PCa) are complex. The present study evaluated whether presence of PCa alters serum T levels. Subjects were 125 patients with clinically localized PCa treated using radical prostatectomy (RP), for whom pretreatment T levels were recorded. We investigated clinical and pathological factors such as pretreatment serum T level, age, pretreatment prostate-specific antigen, Gleason score and pathological stage. Serum T and human luteinizing hormone (LH) levels before and after RP were then compared in 118 of the 125 patients. Mean pretreatment T level was significantly higher in patients with organ-confined PCa (pT2; 4.031.50 ng ml^-1) than in patients with nonorgan-confined cancer (pT3; 3.421.06 ng ml^-1; P=0.0438). No association existed between pretreatment serum T level and pathological Gleason score. After RP, serum T level (5.601.90 ng ml^-1) was significantly elevated compared to preoperative level (3.891.43 ng ml^-1; P<0.0001). In parallel, significant increases were seen in postoperative serum LH level (6.863.64 ng ml^-1) compared to preoperative level (5.112.47 ng ml^-1; P=0.0001). In contrast, differences in serum T levels according to pathological stage disappeared postoperatively (P=0.5513). Significant increases in serum T and LH levels were seen after RP, compared to preoperative levels in parallel. This study suggests that serum T levels are altered by the presence of PCa, supporting the possibility that PCa may inhibit serum T levels with negative feedback in the hypothalamic–pituitary axis.