"We found no evidence that testosterone replacement therapy negatively affects the prostate or its tissues in hypogonadal men following six months of treatment," said Dr. Leonard Marks, co-investigator, Clinical Associate Professor in the Department of Surgery/Urology at the UCLA School of Medicine and founding medical director of Urological Sciences Research Foundation (USRF). "Patients should be comforted by these results, but large-scale, long-term trials are still needed."
Testosterone is a hormone involved in regulating prostate growth, both benign and malignant. When testosterone is boosted, the effect on the prostate is a main concern in older men. However, this study showed that when serum testosterone levels are increased to the mid-normal level, the prostate effects are minimal, at 6-months.
In the randomized, placebo-controlled clinical trial, investigators examined the effects of testosterone (T) in 41 men, ages 50-75 years old with hypogonadism (ADAM score and morning T<300 ng/dL) for a 6-month period. Twenty-one men received testosterone intramuscular injections (150 mg every two weeks); 20 men received placebo. The study was powered to detect a 25% increase in dihydrotestosterone (DHT) in prostate tissue. The groups were comparable at baseline for age, serum T and DHT, Prostate-Specific Antigen (PSA), Prostate Volume (PV) and median prostate levels of T and DHT. Prostate biopsies were conducted at baseline and at 6-months.
No prostate tissue changes attributable to testosterone therapy were found in this trial. Despite marked increases in serum testosterone levels, prostate levels of T and DHT (the hormone that stimulates prostate gland growth) did not change from baseline at 6-months. PSA, PV, tissue biomarkers and indices for atrophy and inflammation also were unchanged after 6-months of treatment. Furthermore, gene expression was not altered, cell proliferation was not accelerated, and histologic cancers were not increased. The study also showed testosterone therapy created positive effects in bones and muscles.
"The prostate appears to be buffered against rather wide fluctuations in serum testosterone levels," said Dr. Marks. "Still, all hypogonadal men considering testosterone therapy, especially older men, must be monitored closely by their physicians prior to and throughout treatment."
The study was conducted at USRF, an independent research center in Los Angeles. In addition to USRF, other contributing sites included Fred Hutchinson Cancer Center, Seattle, WA; Boston University School of Medicine, Boston, MA; Oregon National Primate Research Center, Beaverton, OR; University of Southern California School of Medicine, Los Angeles, CA; Bostwick Laboratories, Richmond, VA; and the Brady Urological Institute of Johns Hopkins University, Baltimore, MD.
The research was supported by the National Institute of Health and by educational grants from Solvay Pharmaceuticals, Inc. and Watson Laboratories. Solvay markets AndroGel®, an FDA-approved topical testosterone replacement gel, and Watson markets Androderm®, an FDA-approved topical testosterone replacement patch.
About Low Testosterone (Low T)
It is estimated that low T affects up to 13 million American men age 45 and older. Because symptoms of low T are subtle and often overlap with other common medical conditions, low T is frequently undiagnosed. Men with chronic conditions, such as diabetes, obesity and hypertension, are more likely to have low T compared to other men. Symptoms of low T may include low sex drive, erectile dysfunction, depressed mood and fatigue. Testosterone treatment, in the form of injections, patches, gels, and a tablet, is designed to elevate a hypogonadal man's testosterone levels into the normal physiologic range and alleviate symptoms. As with any medication, patients should work with their physician to weigh treatment benefits and risks. Information about low testosterone may be found online at: http://www.usrf.org/news/000908-malemenopause.html.
About the Urological Science Research Foundation
Urological Sciences Research Foundation (USRF), a California non-profit organization, was started in 1992 by the founder and current medical director, Leonard Marks, M.D. The primary mission of the foundation is as follows: To help advance the understanding of common urologic problems, increase the range of effective treatments for such conditions, and inform the medical and lay public of these problems and treatments. The Foundation is a self-sustaining, independent operating entity with a full charitable tax exemption (501c3). Funding is derived from donations, research grants, and industry-sponsored contracts. Leadership is provided by a board of directors from the business and professional community.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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