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Labeling on testosterone products sold in the United States indicates that testosterone supplementation is contraindicated in men with a history of prostate cancer and in those thought to be at risk for the disease. A recent study brings the validity of that warning into question.
Boston-Labeling on testosterone products sold in the United States indicates that testosterone supplementation is contraindicated in men with a history of prostate cancer and in those thought to be at risk for the disease. A recent study brings the validity of that warning into question.
At the 2010 AUA annual meeting in San Francisco, Dr. Morgentaler and co-authors Larry Lipshultz, MD, and Mohit Khera, MD, both of Baylor Medical College, Houston, presented initial data on 13 men who had elected to continue or initiate testosterone therapy after they had been diagnosed with biopsy-proven prostate cancer. All had follow-up biopsies.
"First, understand that these men had low-volume, low-risk disease," said Dr. Morgentaler, director of Men's Health Boston and associate clinical professor of surgery at Harvard Medical School. "The question these results raise is that if we can give testosterone without appearing to impact untreated prostate cancer growth, how worried do we really need to be about giving testosterone to men after their primary cancers have been removed or definitively treated?
"One of the strongest so-called 'truths' in oncology for the last 50 years has been that prostate cancer is an androgen-dependent tumor. We have interpreted that to mean that there is a dose-response relationship. More testosterone equals more growth. Less testosterone equals less growth. The data do not support this idea."
Dr. Morgentaler initially accepted the idea of the relationship but began to question it in the 1990s. For a study that was published in JAMA (1996; 276:1904-6), he performed biopsies in men who had normal PSA, normal digital rectal exam, and low testosterone. He found that 11 of 77, or 14%, had prostate cancer.
"This, to me, was astounding because at that time it was universally accepted that men with low testosterone would not develop prostate cancer," he said.
Subsequent study by Dr. Morgentaler and others continued to suggest that testosterone levels were disconnected from the presence of prostate cancer and growth of the disease. He then began to offer testosterone therapy to symptomatic men with untreated prostate cancer.
"If raising testosterone really made cancer grow rapidly, as we've been taught, then studies would show a higher rate of the cancer in men receiving T therapy. They don't," said Dr. Morgentaler.
He noted that many physicians currently give testosterone therapy but few conduct biopsies, despite the one in seven risk of having undetected prostate cancer. However, studies including the one presented by Dr. Morgentaler and his colleagues show no increased risk of developing overt cancer compared to the risk seen in the general population, he noted.
"That is why I thought it would be reasonable to offer testosterone to men with prostate cancer who are being watched," he told Urology Times.
Dr. Morgentaler and others are continuing the studies for several reasons. The benefits, side effects, and risks associated with testosterone are becoming more clearly defined. In addition, an increasing number of patients are inquiring about the therapy.
Dr. Morgentaler has a financial and/or other relationship with Watson Pharmaceuticals, Slate Pharmaceuticals, Solvay Pharmaceuticals, Auxilium Pharmaceuticals, Endo Pharmaceuticals, GlaxoSmithKline, and Eli Lilly.