For Patients & Caregivers
Bottom Line: There is no evidence that PC-SPES can shrink prostate tumors or prolong survival in cancer patients.
PC-SPES is a supplement containing eight herbs (reishi mushroom, baikal skullcap, rabdosia, dyer’s woad, chrysanthemum, saw palmetto, panax ginseng, and licorice.) Scientists do not know which substances in PC-SPES account for its activity. No single botanical or chemical extract appears responsible for the overall effects of this product. Laboratory tests have analyzed the makeup of PC-SPES and have identified estrogen-like compounds that suppress growth and proliferation of human tumor cell lines on contact, including breast, colon, hormone-dependent prostate and hormone-independent prostrate. PC-SPES appears to interfere with the process of tumor cell division and also causes tumor cell death (apoptosis) when cells are exposed to it long enough. The ability of PC-SPES to kill cancer cells may be due to alteration of expression of specific genes involved in regulating the cell cycle, cell structure and response to androgens (such as testosterone). This effect has not been confirmed in humans.
PC-SPES has been found to contain small amount of prescription drugs, including diethylstibestrol and ethinyl estradiol and was taken off the market. It is unclear whether these agents account for its anticancer effects.
In a study of 69 prostate cancer patients taking PC-SPES, blood PSA levels dropped in 82% of patients at two months, in 78% of patients at six months, and in 88% of patients at 12 months. Side effects included many cases of nipple tenderness and one case of phlebitis (vein inflammation). Although a reduction in PSA levels is a good sign, it is more important to determine if the tumors shrink, which was not addressed in this study.
- PC-SPES was recalled and its production was halted in February 2002 because of product contamination with the prescription drugs warfarin, alprazolam, and diethylstilbestrol.
- PC-SPES should not be confused with SPES, an immunostimulant that contains 15 botanicals, sold by BotanicLab. SPES was also recalled for contamination in February 2002.
- Mastalgia (breast pain)
- Gynecomastia (enlargement of the breasts)
- Sexual dysfunction and/or decreased libido
- GI symptoms, diarrhea, and dyspepsia
- Rare: Pulmonary embolism (blood clot in the lungs), deep vein thrombosis (blood clot), phlebitis (inflammation of a vein), edema (swelling), and allergic reactions.
- Case report: Retroperitoneal hemorrhage (bleeding from the lining of the abdominal cavity).
For Healthcare Professionals
PC-SPES is a supplement consisting of eight herbs: Reishi mushroom, baikal skullcap, rabdosia, dyer’s woad, chrysanthemum, saw palmetto, Panax ginseng, and licorice. Patients use it to treat prostate cancer. In vitro testing reveals suppression of human tumor cell lines, including androgen-sensitive and -insensitive prostate cancer (7)(12). It is thought that PC-SPES contains phytoestrogens (17) and other undefined components that contribute to its activity.
Published studies document efficacy of PC-SPES (10)(14)(15)(16); use of PC-SPES resulted in significant decreases in androgen and PSA levels.
Concerns about contamination with DES, warfarin, and alprazolam resulted in a voluntary recall of PC-SPES by Botanic Labs, the manufacturer of PC-SPES in 2002.
- Chrysanthemum mori folium, flower (mum, ju hua)
- Ganoderma lucidum, stem (reishi mushroom, ling zhi)
- Glycyrrhiza uralensis, root (licorice, gan cao)
- Isatis indigotica, leaf (dyers woad, da qing ye)
- Panax notoginseng, root (san qi)
- Rabdosia rubescens, leaf (rubescens, dong ling cao)
- Scutellaria baicalensis, root (baikal skullcap, huang qin)
- Serenoa repens, berry (saw palmetto)
The active components of PC-SPES are unknown. Laboratory analysis of PC-SPES by HPLC, gas chromatography, and mass spectrometry indicate the presence of estrogenic organic compounds different from diethylstilbestrol (DES), estrone, and estradiol. In vitro testing of this extract shows suppressed cell proliferation and reduced clonogenicity in human tumor cell lines, including prostrate, breast, and colon. The predominant cell cycle effect induced by PC-SPES is prolongation of G1 phase; however, apoptosis was observed after exposure of tumor cells to PC-SPES for 48 hours or longer. PC-SPES also inhibits proliferation of LNCaP prostate cell lines, associated with a 60-70% down regulation of the proliferating cell nuclear antigen. Preliminary studies evaluating the viability of prostate cancer cell lines LNCaP, LNCaP apoptosis-resistant derivative, LNCaP-bcl-2, PC3, and DU145 at three concentrations of PC-SPES show inhibited growth at concentrations of 4 mcg/ml or less. Another recent in vitro study indicates its cytotoxicity may be due to alteration of expression of specific genes involved in regulating the cell cycle, cell structure and androgen response. No single botanical or chemical extract appears responsible for the overall effects of this product. PC-SPES has been found to contain small amount of diethylstibestrol and ethinyl estradiol. It is unclear whether these agents account for its anticancer effects.
- Concerns about product contamination with prescription drugs, such as DES, warfarin, and alprazolam resulted in a voluntary recall of PC-SPES by Botanic Labs, the manufacturer of PC-SPES in 2002.
- PC-SPES should not be confused with SPES, an immunostimulant that contains 15 botanicals, sold by BotanicLab. SPES was also recalled in 2002 because of contaminated products.
Oh WK, et al. Prospective, Multicenter, Randomized Phase II Trial of the Herbal Supplement, PC-SPES, and Diethylstilbestrol in Patients With Androgen-Independent Prostate Cancer. J Clin Oncol 2004;22
This is a randomized phase II study involved 90 patients with androgen independent prostate cancer. Patients received either PC-SPES capsules 3 times daily or diethylstilbestrol (DES) 3mg orally daily. The study was discontinued prematurely after contaminants, including DES and ethinyl estradiol, were detected in PC-SPES. Available data suggests PC-SPES has moderate activity in decreasing prostate-specific antigen level. However, it is unclear which components account for this activity.