Low serum testosterone level predicts worse response to endocrine therapy in Japanese patients with metastatic prostate cancer.

Patients with prostate cancer generally respond to androgen withdrawal therapy, but progression to androgen-independence is frequently observed later. To examine whether pretreatment serum androgen status could predict disease progression in metastatic prostate cancer, pretreatment serum testosterone, histological grade, extent of bony metastasis, serum prostate-specific antigen (PSA) response to hormone therapy, and prognosis of the 40 patients with untreated metastatic prostate cancer who received endocrine therapy were evaluated. Although there were no differences in age, pretreatment PSA level, extent of bony disease and histological grade between patients with normal testosterone and those with low testosterone, PSA response after endocrine therapy was better in normal testosterone group. There was a significantly longer interval to disease progression in patients with normal testosterone than in those with low testosterone. The patients with metastatic prostate cancer with low serum testosterone were in the high risk group of worse response to endocrine therapy. Additional therapy might be considered in those patients.