Activity of the herbal combination, PC-SPES, in the treatment of patients with androgen-independent prostate cancer

Abstract

Objectives. To retrospectively evaluate the response to treatment with PC-SPES, an herbal supplement, because patients with androgen-independent prostate cancer have limited treatment options. Methods. A retrospective analysis was performed of patients with prostate cancer progression despite androgen ablation therapy who were treated with PC-SPES (3 capsules twice daily). We explored potential predictors of response. Results. Twenty-three patients with androgen-independent prostate cancer were treated. The median age was 70 years. Eighteen patients had received prior secondary hormonal treatment and 10 prior chemotherapy. With a median follow-up of 8 months, 20 (87%; 95% confidence interval 66% to 97%) of 23 patients experienced a post-therapy decline in prostate-specific antigen (PSA). The median decline in PSA among these patients was 40% (range 1% to 88%). Of 23 patients, 12 (52%; 95% confidence interval 31% to 73%) had a greater than 50% decline in PSA. The median duration of the PSA response was 2.5 months (range 1 to 9+); the median time from the start of therapy to PSA progression was 6 months (range 2 to 12). Seven patients died of progressive prostate cancer. Toxicity was mild and included nipple tenderness, nausea, and diarrhea. One patient with a known history of coronary artery disease developed angina. In univariate analyses, older patients and those with a longer duration of initial androgen ablation therapy were more likely to respond to PC-SPES. Conclusions. PC-SPES is a well-tolerated and active treatment for androgen-independent prostate cancer. Additional testing is necessary to identify the active components of PC-SPES and its role in the treatment of patients with androgen-independent prostate cancer.