The effects of phytotherapeutic agents on prostate cancer: an overview of recent clinical trials of PC SPES.

The clinical effects of the dietary supplement PC SPES will be reviewed. This herbal extract is a combination of 1 US herb and 7 Chinese herbs shown to be active against both androgen-dependent and androgen-independent prostate cancer. Anecdotal reports on the effectiveness of this agent have led to several clinical trials. These clinical trials have shown prostate-specific antigen partial response rates and overall improvements in quality of life. Although these studies have concluded that there is a possible estrogenic component, evidence exists that this is not the sole reason for the efficacy of PC SPES. At this point, clinical trials have validated PC SPES as an option for patients with prostate cancer, but further study is needed to pinpoint the exact mechanism of action.

PC-SPES, a dietary supplement for the treatment of hormone-refractory prostate cancer.

OBJECTIVE: To assess the effectiveness of PC-SPES, a dietary supplement containing eight herbal extracts, which is a popular alternative therapy among patients with hormone-refractory prostate cancer; anecdotal reports claim that this agent provides relief of metastatic pain, improvements in quality of life and reduction of prostatic specific antigen (PSA) level. PATIENTS AND METHODS: Sixteen men treated for advanced metastatic prostate cancer (stage D3) with either orchidectomy or a luteinizing-hormone releasing hormone agonist, with or without anti-androgen, were enrolled into a prospective clinical trial to evaluate the possible toxic and beneficial effects of PC-SPES. After hormone-ablative therapy had failed, and with established disease progression, all patients received supplemental treatment with PC-SPES (2.88 g daily) for 5 months. Hormonal therapy was continued throughout the trial to avoid the known withdrawal effect of anti-androgen on PSA levels. RESULTS: The supplemental intake of PC-SPES was associated with significant (P<0.05-0.01) improvements in quality-of-life measures, reductions in patient's pain ratings (P<0.05-0.01), and a decline in PSA levels (P<0.01), with no major side-effects. CONCLUSIONS: These results support the anecdotal reports of the beneficial effects of PC-SPES as a comparable alternative to current management regimens in hormone-refractory prostate cancer. However, no conclusions can be drawn about the long-term effects of this new herbal therapy.