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CLINICAL EFFECTS OF SAW PALMETTO EXTRACT IN MEN WITH SYMPTOMATIC BPH

Leonard S. Marks, Frederick J. Dorey, Maria L. Macairan, Paul Bryan C. Santos, Joel B. Garris, Debra K. Jahner, Kerry A. Stonebrook, Los Angeles, CA; Alan W. Partin, Baltimore, MD; Varro E. Tyler, West Lafayette, IN. (Presented by Dr. Marks)

INTRODUCTION -- Saw palmetto extract (SPE) is used by many men to self-treat symptomatic BPH, but the mechanism of action is not known, and safety - efficacy data from the U.S. are lacking. Thus, we performed a randomized trial of a SPE/herbal blend, using a pharmaceutical-study model.

METHODS -- 44 men (age = 64 years; symptom score, IPSS = 18; maximum flow, Qmax = 10.8 cc/sec; post-void residual, PVR = 72 cc; prostate volume, PV = 55 cc; PSA = 3.4 ng/ml) were randomized to a placebo or SPE arm of a 6-month double-blind study. Rigid inclusion / exclusion criteria were followed. A one-month, single-blind, placebo lead-in (between baseline and randomization) preceded the double-blind period. One lot of standardized SPE extract was used throughout; dosage was 320 mg/day. Prostate MRI and ultrasound-guided biopsy for tissue study were performed at baseline and after 6 months of randomization.

RESULTS -- 43 men completed the study, 41 with a follow-up biopsy. No adverse events related to treatment were seen. Compliance by pill count was 95%. A panel of 26 blood tests showed no significant changes. A placebo effect (~15% improvement, p=NS) was seen during the lead-in period for SS and Qmax. At 6 months, the SPE group showed a further decrease in SS of 2.9 points and the placebo group a further decrease of 2.6 points (p=NS); Qmax increased a further 1.1 cc/sec in the SPE group but decreased 0.8 cc/sec in the placebo group (p=NS). No significant changes were seen in PVR, PV (whole or transition zone), or serum levels of PSA (total or free), testosterone, dihydrotestosterone, or estradiol. After the blind was broken at 6 months, 19 of 21 SPE patients elected to continue this treatment.

CONCLUSIONS -- The SPE/herbal blend appeared to be a safe, somewhat effective treatment, which was desirable to most patients. No hormonal changes were observed. The modest SS and Qmax improvements over placebo in this small group of SPE-treated men followed for 6 months might become more pronounced with more patients and/or longer follow-up. This belief is supported by the clear-cut SPE-induced change in prostate histology of these men (p<0.01), which is described in the companion abstract.


PROSTATE TISSUE EFFECTS OF SAW PALMETTO EXTRACT IN MEN WITH SYMPTOMATIC BPH.

Jonathan I. Epstein, Alan W. Partin, Inpakala Simon, Natasha Kyprianou, Baltimore, MD; David L. Hess, Portland, OR; Gail Prins, Chicago, IL, Leonard S. Marks, Frederick J. Dorey, Maria L. Macairan, Paul Bryan C. Santos, Los Angeles, CA; (Presented by Dr. Epstein)

INTRODUCTIONS -- A mechanism of action of saw palmetto extract (SPE) in human prostate is unknown. Suggested mechanisms include inhibition of androgen action and an anti-inflammatory effect. We evaluated these possibilities by study of prostate biopsy specimens obtained before and after treatment from men in a 6-month randomized clinical trial of SPE vs. placebo.

METHODS -- Patient characteristics and study design are described in the companion abstract. Ultrasound-guided sextant biopsy for tissue study was available on 41 men, performed at baseline and after 6 months of placebo (N=20) or SPE (N=21). The 82 tissue samples were batch-studied by routine histology; by morphometry for quantitative tissue composition of the inner and outer gland; by use of a histopathologic scoring system for inflammation, acute and chronic, and for atrophy; by immunohistochemical assessment of apoptosis, cell proliferation, and androgen receptor expression; and by a tissue homogenate radioimmunoassay for testosterone and dihydrotestosterone (expressed as ng/g of prostate tissue).

RESULTS -- A contraction in the transition zone epithelium, from 17.8% before to 10.7% after 6 months of treatment, was found in the SPE group (p<0.01). In a parallel, independent analysis, the epithelial atrophy score increased from 25.2% before to 40.9% after SPE (p<0.01). In placebo patients, no significant changes were seen in any tissue measures. None of the other tissue studies revealed significant changes from baseline during SPE treatment.

CONCLUSIONS -- SPE appears to exert a suppressant effect on the prostatic epithelium, especially in the TZ. Since no alteration in prostatic androgen metabolism or apoptosis markers could be demonstrated, the data suggest that the effect is mediated by some non-hormonal control mechanism. How epithelial suppression relates to clinical effects, in the absence of prostate volume contraction, is not clear. However, the finding that use of SPE can in 6 months lead to a statistically significant epithelial involution in the human prostate should serve as an impetus to further investigation.

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