Testosterone and Prostate Cancer -Dispelling the Myth that Testosterone Causes Prostate Cancer
One of the more common concerns that many men have, especially if they have a family history of prostate cancer or other non-cancerous prostate problems, is that being treated with testosterone will increase their chances of having prostate disease in the future. Some have even heard that testosterone actually causes prostate cancer. To make matters worse, these sentiments are often shared with patients by their primary care physicians. The myth that testosterone replacement therapy causes prostate cancer has been deeply rooted in the western medical paradigm for over sixty years.
Where does this myth come from?
In the article Testosterone Replacement Therapy and Prostate Risks: Where’s the Beef? By Abraham Morgentaler, MD, the author writes that more than 60 years ago, researchers studied the effects of castration on people with prostate cancer. They observed that the cancer regressed. Since the testicles were removed, no more testosterone was present. They concluded that since removing testosterone led to regression of prostate cancer that the cause of the cancer must have been the testosterone. The same effect was observed in patients who underwent pharmacological lowering of serum testosterone.
However, we now know that there is a lot more to this. The male body produces estrogen by converting testosterone directly into estradiol. Men need some estrogen, but they don’t have ovaries to produce it. Instead, an enzyme called Aromatase converts testosterone into estradiol, a potent estrogen. Normally, as life progresses, the amount of estrogen is kept at a particular level, but when a man with low testosterone has his levels brought to an optimal level very suddenly, the activity of Aromatase can result in drastically high estrogen (estradiol) levels. Well, guess what; Estradiol excess has been linked to prostate cancer in more recent studies. This is just one possible effect of increased estradiol levels in men. Many others can occur, and this is why many doctors recommend their patients take the aromatase inhibitor, Anastrozole (Arimidex). By using this medication along with testosterone, the estradiol levels can be kept to optimal levels for a male patient.
So, let us review. Physical or chemical castration results in almost no testosterone, and prostate cancer regresses in individuals who have undergone such castration. However, we can now say that since testosterone was nearly absent, and since men get their estradiol by converting testosterone into estradiol, that there was not enough testosterone present to create the offending estradiol. No testosterone = no estradiol. No estradiol = regression of cancer.
Dr. Edward Friedman has written a book called The New Testosterone Treatment; How You and Your Doctor Can Fight Breast Cancer, Prostate Cancer, and Alzheimer’s. In it, he uses the latest research to explain what he calls The Hormone Receptor Model for how prostate (and breast) cancer emerge, and he does so in a language that most people can understand. By understanding the different testosterone and estrogen receptors and their role in prostate cancer, he has determined that prostate cancer can actually be treated with testosterone therapy so long as the estradiol is kept to a minimal level.