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PC-SPES is a mixture of herbs that was sold as a complementary and alternative medicine (CAM) treatment for people with prostate cancer. The mixture contains these 8 herbs:
PC-SPES was taken off the market because some batches were found to contain prescription medicines in addition to the herbs. Clinical trials of PC-SPES that were underway were stopped. There are products being sold now as substitutes for PC-SPES, but they are not the same mixture. Since the only company licensed to make PC-SPES is no longer in business, PC-SPES is not legally available in the United States.
Most of the herbs in PC-SPES have been used in traditional Chinese medicine (TCM) for many health problems, including prostate problems, for hundreds of years. A chemist in New York and a doctor/herbalist in China worked together to create the mixture. In 1997, a company was formed to make PC-SPES and sell it in the United States without a prescription. Interest in PC-SPES grew, and researchers began looking at it. Tests found that some batches of PC-SPES contained one or more of the following drugs, which are not found in nature:
Because these drugs are to be used only by prescription and could be harmful to some people, PC-SPES was taken off the market in 2002.
In lab tests, each herb used in PC-SPES has been reported to help keep cancer cells from growing or to help prevent cell damage that can lead to cancer and other diseases.
PC-SPES was reported to slow the growth of prostate cancer but did not cure it. It is not known how PC-SPES works in the body. Some of the herbs in the mixture contain phytoestrogens, which are estrogen-like substances found in plants. Estrogen can cause the testicles to stop making testosterone, which makes some prostate cancers grow. Patients' responses to PC-SPES were similar to responses to estrogen therapy using DES. The DES found in some batches of PC-SPES, however, may not have been enough to cause all of the estrogen-like effects that were seen in users of the mixture. There is some evidence that the mixture works in a different way than DES does, and that PC-SPES alone (without DES in it) may fight prostate cancer.
PC-SPES has also shown anticancer effects on prostate cancers that do not depend on testosterone and on other types of cancer. This suggests that PC-SPES may have anticancer qualities other than its estrogen-like effects.
PC-SPES is taken by mouth in capsules.
Studies of PC-SPES in test tubes and using rats showed that it might keep cancer cells from growing. These studies were done, however, before it became known that some batches of the product contained unlisted prescription medicines. Also, the product was not standardized (different batches of PC-SPES were found to contain different strengths of the herbal ingredients). For these reasons, the results of the lab tests and animal studies are not considered to be good evidence.
Clinical trials of PC-SPES had begun before the product was taken off the market. In these trials, PC-SPES was reported to improve quality of life, reduce pain, and lower PSA (prostate specific antigen) levels in patients with prostate cancer. Rising PSA levels can be a sign that prostate cancer is growing.
After it was learned that some batches of PC-SPES contained prescription medicines, ongoing studies were stopped and previous study results came into question. The responses reported in the studies may have been caused by the prescription medicines that were in the PC-SPES, as well as by the herbal ingredients. Also, since different batches of PC-SPES contained different ingredients, the studies cannot easily be compared.
Common side effects were the same as those reported with estrogen therapy:
There were other, less common, side effects:
PC-SPES may also change the way drugs, including anticancer drugs, work in the body. It may cause drugs to be more or less effective, or cause effects on the body that are not expected.
The U.S. Food and Drug Administration has not approved PC-SPES for use in cancer treatment. It is not legally sold in the United States.
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Changes were made to this summary to match those made to the health professional version.
Complementary and alternative medicine (CAM)—also referred to as integrative medicine—includes a broad range of healing philosophies, approaches, and therapies. A therapy is generally called complementary when it is used in addition to conventional treatments; it is often called alternative when it is used instead of conventional treatment. (Conventional treatments are those that are widely accepted and practiced by the mainstream medical community.) Depending on how they are used, some therapies can be considered either complementary or alternative. Complementary and alternative therapies are used in an effort to prevent illness, reduce stress, prevent or reduce side effects and symptoms, or control or cure disease.
Unlike conventional treatments for cancer, complementary and alternative therapies are often not covered by insurance companies. Patients should check with their insurance provider to find out about coverage for complementary and alternative therapies.
Cancer patients considering complementary and alternative therapies should discuss this decision with their doctor, nurse, or pharmacist as they would any therapeutic approach, because some complementary and alternative therapies may interfere with their standard treatment or may be harmful when used with conventional treatment.
It is important that the same rigorous scientific evaluation used to assess conventional approaches be used to evaluate CAM therapies. The National Cancer Institute (NCI) and the National Center for Complementary and Alternative Medicine (NCCAM) are sponsoring a number of clinical trials (research studies) at medical centers to evaluate CAM therapies for cancer.
Conventional approaches to cancer treatment have generally been studied for safety and effectiveness through a rigorous scientific process that includes clinical trials with large numbers of patients. Less is known about the safety and effectiveness of complementary and alternative methods. Few CAM therapies have undergone rigorous evaluation. A small number of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that may help patients feel better and recover faster. One example is acupuncture. According to a panel of experts at a National Institutes of Health (NIH) Consensus Conference in November 1997, acupuncture has been found to be effective in the management of chemotherapy-associated nausea and vomiting and in controlling pain associated with surgery. In contrast, some approaches, such as the use of laetrile, have been studied and found ineffective or potentially harmful.
The NCI Best Case Series Program, which was started in 1991, is one way CAM approaches that are being used in practice are being investigated. The program is overseen by the NCI's Office of Cancer Complementary and Alternative Medicine (OCCAM). Health care professionals who offer alternative cancer therapies submit their patients' medical records and related materials to OCCAM. OCCAM conducts a critical review of the materials and develops follow-up research strategies for approaches deemed to warrant NCI-initiated research.
When considering complementary and alternative therapies, patients should ask their health care provider the following questions:
National Center for Complementary and Alternative Medicine (NCCAM)
The National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health (NIH) facilitates research and evaluation of complementary and alternative practices, and provides information about a variety of approaches to health professionals and the public.
CAM on PubMed
NCCAM and the NIH National Library of Medicine (NLM) jointly developed CAM on PubMed, a free and easy-to-use search tool for finding CAM-related journal citations. As a subset of the NLM's PubMed bibliographic database, CAM on PubMed features more than 230,000 references and abstracts for CAM-related articles from scientific journals. This database also provides links to the Web sites of over 1,800 journals, allowing users to view full-text articles. (A subscription or other fee may be required to access full-text articles.) CAM on PubMed is available through the NCCAM Web site. It can also be accessed through NLM PubMed bibliographic database by selecting the "Limits" tab and choosing "Complementary Medicine" as a subset.
Office of Cancer Complementary and Alternative Medicine
The NCI Office of Cancer Complementary and Alternative Medicine (OCCAM) coordinates the activities of the NCI in the area of complementary and alternative medicine (CAM). OCCAM supports CAM cancer research and provides information about cancer-related CAM to health providers and the general public via the NCI Web site.
National Cancer Institute (NCI) Cancer Information Service
U.S. residents may call the NCI Cancer Information Service toll free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 8:00 am to 8:00 pm. A trained Cancer Information Specialist is available to answer your questions.
Food and Drug Administration
The Food and Drug Administration (FDA) regulates drugs and medical devices to ensure that they are safe and effective.
Federal Trade Commission
The Federal Trade Commission (FTC) enforces consumer protection laws. Publications available from the FTC include:
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PDQ also contains information on clinical trials.
A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Listings of clinical trials are included in PDQ and are available online at NCI's Web site. Descriptions of the trials are available in health professional and patient versions. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237).
Last Revised: 2013-01-18
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