NOTE: The information in this summary is no longer being updated and is provided for reference purposes only.
This complementary and alternative medicine (CAM) information summary provides an overview of the use of PC-SPES as a treatment in people with cancer. The summary includes a brief history of PC-SPES research, the results of clinical trials, and possible adverse effects of PC-SPES. Included in this summary is a discussion of the contamination of PC-SPES and its withdrawal from avenues of distribution.
This summary contains the following key information:
- PC-SPES is a patented mixture of eight herbs.
- PC-SPES was sold as a dietary supplement to support and promote healthy prostate function.
- Each herb used in PC-SPES has been reported to have anti-inflammatory, antioxidant, or anticarcinogenic properties.
- PC-SPES was recalled and withdrawn from the market because certain batches were contaminated with Food and Drug Administration–controlled prescription drugs.
- The manufacturer is no longer in operation, and PC-SPES is no longer being made.
- There is evidence from both laboratory and animal studies to suggest that PC-SPES had some effect in inhibiting prostate cancer cell growth and prostate-specific antigen (PSA) expression, but it is not known whether these results were caused by adulterants such as diethylstilbestrol, which is an estrogenic compound, the herbs in PC-SPES, or their combination.
- Evidence from clinical trials has shown that PC-SPES lowers PSA and testosterone levels in humans, but it is not known whether these results were caused by adulterants, the herbs in PC-SPES, or their combination.
- There is some evidence to suggest that PC-SPES has some anticancer effects that are not related to estrogen-like activity.
- Although there are products that claim to be substitutes for PC-SPES, they are not the patented original formulation. Few of these products have been the subject of laboratory or clinical trials reported in the peer-reviewed medical literature.