Saw Palmetto Warning : Problems with Detecting Prostate Cancer?

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The purpose of this letter is to alert physicians and the general public to the potential implications regarding the detection and treatment of prostate cancer involved with the use of an alternative supplement sold in health food stores called saw palmetto. Prostate cancer is the most commonly diagnosed cancer in American men. In 1996, an estimated 317,100 new cases of prostate cancer, and 41,400 deaths from prostate cancer will be found, among men in the United States. It is the second most common cause of death in men older than 55. Early detection is the most important factor for cure! We are detecting prostate cancer within the past decade with increasing frequency, and many patients with this condition are receiving such treatments as radical prostatectomy and radiation therapy for cure.

Although refinements in PSA-based testing have contributed substantially to the increased detection rate of prostate cancer, the incidence of disease was increasing dramatically even before the detection of PSA was possible. Self medication for prostate disorders has increased throughout the US and the rest of the world. Saw palmetto in particular raises concerns for urologists regarding their ability to diagnose and treat prostate cancer. I have seen many patients who have placed themselves on this herb. Its use is advised in advertisements and other marketing for treatment and prevention of benign prostatic hyperplasia (BPH), prostatitis, and "urinary difficulty" in men.

The extract comes from the berries of the palm tree saw palmetto (Serenoa Repens, Serenoa Serrulata), which is indigenous in the Atlantic southeast coast of North America from South Carolina to Florida and native to the West Indies.The plant grows six to 10 feet tall, with a crown of large spiny-leaves that form a circular, fan-shaped outline. The berries are deep red-brown or black and are oblong and about one inch long. The extract from these berries is cheap and easy to purchase. Word has been spread via direct marketing, as well as by advertisements in magazines and throughout the Internet. Reports, mostly in the European literature, suggest that use of saw palmetto can decrease the size of the prostate and improve urinary symptoms (dose dependent) after months of use.[1] No "well done" long-term, double-blind, placebo-controlled studies of saw palmetto have been done to date.[2] Although saw palmetto does not affect certain hormonal levels, there is clinical evidence, however, to suggest that its mechanism of action is similar to that of the commonly prescribed prostate drug finasteride (Proscar). For example, several animal studies[3, 4] suggest that saw palmetto has a similar effect on competitively inhibiting the binding of dihydrotestosterone (DHT) and blocking the conversion of testosterone to DHT, via its inhibition of 5-alpha reductase.

Saw palmetto's primary therapeutic action is to inhibit 5-alpha reductase in forming DHT and to a lesser extent, 3-alpha reductase, and to block the action of DHT to receptors on prostate cells via 3-ketosteroid reductase. Research has also shown an anti-inflammatory[5] and antiestrogenic[3, 6,7] effect of Serenoa Repens. Use of saw palmetto in >patients with BPH results in reduction in the size of the prostate.[5 ] With finasteride, however, studies have shown that 6 to 12 months of >treatment with 5 mg of finasteride daily can reduce prostate volume, DHT, and prostate-specific antigen (PSA) levels by 50 percent.[8] Therefore, any patient placed on finasteride must have a baseline PSA and digital rectal examination.The mechanism of action mimics the pharmacologic action of finasteride, which has recently been documented to be of little physiologic value compared with a placebo or alpha blockers.[9] The purified extract of saw palmetto contains 85% to 95% fatty acids and sterols. Unfortunately, there are many forms of this extract on the market, containing additives and many combinations of other herbs, vitamins, and minerals. Consequently the consumer does not know exactly what he is purchasing. Saw palmetto has been used in Europe for more than 20 years. Research there, however, has included clinical studies showing its clinical urologic effects versus a placebo. [10] Only one study measured the PSA levels prematurely after 3months "the treatment did not significantly alter PSA concentrations in these patients."[13] However 5-alpha reductase inhibitors will reduce the PSA levels by average of 50% after 6-12 months of use, invalidating this study on PSA. Consequently of most significance is the lack of well planned "long term clinical studies" concerning the effects of saw palmetto on "lowering the PSA" levels after 6-12 months! Any interference with PSA makes this test useless as a diagnostic tool for prostate cancer.

The use of saw palmetto is not regulated by the FDA (its use falls under the guidelines for food supplements). In my own clinical practice, I have seen many patients on saw palmetto who were embarrassed to bring this to my attention. I have also noticed a dramatic drop in PSA levels when patients have been on this herb for many months, making my clinical diagnostic determination of prostate cancer more complex. Any 5-alpha reductase inhibitor--whether saw palmetto or finasteride--will reduce PSA significantly. I quote Dr. Julian Whitaker in his book, Prostate Report-Prevention and Healing[11]: "When one of my patients has an elevated PSA, I don't rush him off for a biopsy. Instead, I encourage him to go on a low-fat diet, and I prescribe a daily course of serenoa repens extract, 360 mg a day, along with zinc and a regimen of antioxidant vitamins and minerals. We then recheck his PSA level periodically, and it has been my clinical experience that, in many cases, the PSA gradually falls." This is an example of how an underlying condition, possibly prostate cancer, can potentially be concealed by losing the sensitivity of the PSA diagnostic test. Although refinements in PSA-based testing have contributed substantially to the increased detection of early prostate cancer, the incidence of the disease is increasing dramatically although the detection by PSA-incidence is alling since 1992. [12] Possibly the confusion in the literature about when to and who to treat prostate cancer has contributed to this decline. So has the introduction of medical therapy with 5-alpha reductase inhibitors and herbs introduced during the same time period. The most disturbing aspects of self-treatment with such herbal remedies are their potential effects in masking PSA, which has revolutionized our ability to pick up prostate cancer. If one curtails the ability to detect prostate cancer by PSA, many cancers will progress undetected until it is too late, resulting in Stage D Disease.

As a clinical urologist, I feel that the public deserves and has the right to know these possible consequences--further research is needed. I am not saying that saw palmetto or finasteride should never be used, but only that they should be used with careful medical supervision and after obtaining a baseline PSA and digital rectal exam. Although saw palmetto is an herb, we must treat it as a medicine. Since saw Palmetto can act as a 5-alpha reductase inhibitor, thereby potentially interfering with PSA levels in men and decrease prostate cancer detection, it is imperative that men get a baseline PSA level (as is recommended by the FDA for Finasteride, but not for the unregulated use of Saw Palmetto). Men self -medicating themselves with this herb are not aware of this detrimental effect. We are in a new world where patients are more inclined to self-treat their medical conditions with alternative means. I believe that there is some merit to this, with proper guidance by qualified individuals. The escalating cost of medicines in the US has provoked Americans to seek more cost-effective approaches, which is one of the many dilemmas that our present health care system has to address promptly. Doctors need to be better educated about nutrition and alternative medicine. Physicians in the US are not informed about alternative botanical medicine; we are far behind the European community in this regard. I believe that there are many benefits to botanical treatments for many ailments when combined with nutritional approaches. We must discover the alternative approaches that are accessible to us, while simultaneously using these remedies when appropriate and combining them with conventional medical treatment. We must start to incorporate this into our medical schools and residency programs so that we maintain the doctor-patient relationship. To render a proper diagnostic evaluation, doctors and patients must communicate with each other, which means that patients should inform their doctors about their use of any over-the-counter vitamins, minerals, or herbs. A man who treats himself may have a fool for a patient!

Arnaldo F. Trabucco, M.D

Department of Surgery, Division of Urology
Catholic Medical Center of Brooklyn & Queens
St. Johns Hospital
Elmhurst, NY


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10. Dreikorn K., Schonhofer PS: Status of phytotherapeutic drugs in treatment of benign prostatic hyperplasia. Urologe A 1995 Mar; 34(2): 119-129.

11. Whitaker J.: The Prostate Report--Prevention and Healing, chapter 7, p 44. 1994, Phillips Publishing, Inc.

12. Stephenson R., et a.: "The fall in incidence of prostate carcinoma: On the down side of a prostate specific antigen induced peak in incidence"--Data from the Utah Cancer Registry. Cancer 1996; 77: 1342-1348.

13.Braeckman J.: The extract of sereona repens in the treatment of benign prostatic hyperplasia: a multicenter open study.Current Therapeutic Research (Vol. 55, No. 7,July, pp 776-785) 1994.