Herbal Treatments May Affect the Screening Test for Prostate Cancer

James Metz, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: November 1, 2001

It is estimated 180,400 men will be diagnosed with prostate cancer in the year 2000. Most patients are screened for prostate cancer with a blood test that detects a substance called Prostate Specific Antigen (PSA). Screening for PSA has been so successful that most cases of prostate cancer are picked up by this screening test and patients are being diagnosed at earlier stages of disease.

With an increased utilization of herbal therapies, it has been found that a number of these natural supplements may affect the PSA blood test. Most of these herbs are touted as "supporters of prostate health". You can see the advertisements on television, read them in the press, and hear them on the radio. Because these herbal therapies are natural supplements, they are not regulated by the Food and Drug Administration (FDA). The only requirement is that they do not claim effectiveness against a particular disease. So the manufacturers use vague claims such as "supporting male wellness" or "supporting prostate health." Herbal therapies that may lower the PSA blood test include Saw Palmetto, PC-SPES, Lycopene, and other phytoestrogen combinations.

These natural therapies are medications. They can affect a number of processes within the body. Because they fall under the heading of "supplements", they do not undergo the rigorous scientific testing expected of medications approved by the FDA. Also, since they are not regulated, supplements from different companies may have completely different content. In fact, frequently there are variations of concentration of herbal batches from the same company.

Many men take these supplements without knowing some of these herbs can affect the PSA blood test used to detect prostate cancer early. There is a possibility some of these medications will cause a delay in diagnosis of prostate cancer. It is important for your physician to know if you are taking these therapies because they may place less reliance on the traditional values used for normal PSA. Also they may place more importance on regular prostate physical examinations. If there is a slight trend upward in the PSA, even when it is in the normal range, your physician may be more likely to recommend a biopsy to rule out a cancer. The bottom line—the normal thresholds used by physicians for further evaluation need to be changed when patients are using therapies that may cause a decrease in the PSA.

For those patients treated for prostate cancer with surgery or radiation, using herbal therapies without the knowledge of your physician may cause them to make false assumptions of effectiveness of a conventional therapy. This may cause a delay in the evaluation of recurrence of prostate cancer and the institution of appropriate therapy.

Always discuss the utilization of unconventional medical therapies with your physician. This will allow informed recommendations to be made for management of your condition. OncoLink supports the evaluation of these herbal medicines in scientific clinical trials. Hopefully, we will gain more insight into these therapies with rigorous scientific testing.