Does Testosterone Cause Prostate Cancer?
Mainstream medical practitioners often have stated that prostate cancer, which in 2003 was responsible for the deaths of more than 29,000 men in the US, is caused by testosterone. Fortunately, the Institute of Medicine includes some data showing that optimal levels of testosterone do not cause prostate cancer, and in fact may protect against this major killer of elderly men. On p. 90, the authors state:

“population-based studies clearly document the relationship between aging and both increases in prostate cancer incidence rates and decreases in circulating [and free] testosterone levels. While this relationship does not equal causality, the findings do raise intriguing hypotheses regarding the influence of testosterone on inhibiting prostate carcino-genesis.”

Estrogen’s Role in Prostate Cancer
Unfortunately, while the Institute of Medicine spends 11 pages (pp. 87-98) detailing testosterone’s effect on the prostate, it offers no discussion of the possible effects of estrogen on prostate and its role in prostate cancer. The belief that estrogen, rather than testosterone, is one of the prime hormonal initiators of prostate cancer is based on the fact that while testosterone levels are highest in young men, prostate cancer essentially is never seen in this population. It is only in older men, who have lower levels of testosterone but higher levels of estrogen and its breakdown products, that prostate cancer is a significant health threat. Animal studies have shown that male rats treated with testosterone alone showed significantly less prostate growth compared to animals treated with both testosterone and estrogen.16 A 1993 study showed that men treated with DHT (which cannot convert to estrogen) saw a reduction in the size of their prostate with no sign of prostate cancer.17 An article published in 2003 in the World Journal of Urology sums up the estrogen-prostate cancer link succinctly: “Estrogenic stimulation through estrogen receptor alpha in a milieu of decreasing androgens [testosterone] contributes significantly to the genesis of benign prostates hyperplasia, prostate dysplasia, and prostate cancer.”18

The Institute of Medicine’s Recommendations
With all the positive studies cited by the Institute of Medicine, it would be reasonable to expect the authors to conclude that testosterone supplementation, to even the most conservative-minded researcher, has been shown to be efficacious for a variety of andropause-related symptoms. Unfortunately, that is not the case. In fact, the authors do not even acknowledge that low testosterone contributes to andropause in any way, shape, or form, as seen in the following quote on p. 100:

“Endogenous testosterone levels clearly decline with aging, but it is not clear if lower levels of serum testosterone affect health outcomes in older men.”

Following this remarkable statement, the authors then conclude on p. 100:

“A systematic review of the medical literature on testosterone therapy, particularly placebo-controlled trials in older men, demonstrated that there is not clear evidence for any of the health outcomes examined.”

Scanning electron micrograph of prostatic cancer cell magnified 6000x..

Given the mind-set exemplified by the previous statement, the Institute of Medicine’s recommendations and conclusions should come as no surprise. On pp. 117-167, the authors detail the committee’s key conclusions, considerations, and recommendations, based on their rather skeptical view of testosterone’s effect on the aging process in men and the use of testosterone supplementation. Their first recommendation is to conduct trials of testosterone supplementation only in older men—those aged 65 and above—and to focus on testosterone supplementation as a therapeutic intervention rather than a preventive measure. The problem here is that it is well established—and even acknowledged by the Institute of Medicine—that in most men, testosterone levels begin falling while they are in their forties. While it is certainly worthwhile to try to treat debilitating symptoms of any disease or pathological process, be it an infection or aging, it is almost always better to try to prevent symptoms rather than treat them once they are in place.

The recommendations continue with the idea of starting research trials with studies to determine whether there is any benefit to testosterone supplementation, and if so, then conducting longer-term trials. The glaring problem with these recommendations is that a significant number of clinical trials already have been conducted—many referenced by the Institute of Medicine—that prove the efficacy of testosterone supplementation for treating a variety of andropause-related symptoms. In addition, longer-term studies of up to three years already have been conducted and have established the usefulness of testosterone supplementation in both middle-aged and elderly men. In the journal The Aging Male, researchers recently presented the findings of a three-year study of 122 men, aged 19 to 67, who were treated with testosterone gel.19 As with numerous earlier studies, the study authors found that long-term treatment with testosterone supplementation causes a statistically significant improvement in bone mineral mass and sexual desire, an increase in muscle mass, and a decrease in fat mass.

The Institute of Medicine’s final recommendation concerns the safety of the men participating in the testosterone supplementation trial. To accomplish this, the committee would set up strict exclusion criteria, mandate careful monitoring of markers of prostate function such as PSA (prostate specific antigen) levels, and seek to ascertain whether long-term testosterone supplementation can cause a rise in prostate cancer. While these recommendations are commendable, significant omissions also are obvious, such as failing to include monitoring of SHBG and estrogen levels along with the use of estrogen blockers (aromatase-inhibitors).

It is puzzling, at the very least, why the Institute of Medicine fails to even mention the significant effect of rising estrogen levels on prostate cancer when a substantial amount of well-researched literature has been published on this very subject.

Conclusions of the Institute of Medicine
In the Institute of Medicine book’s final pages (pp. 163-7) preceding the appendixes, the authors cast a derisive eye on the myriad reports showing the effectiveness of testosterone supplementation, concluding:

“The trials that have been conducted do not show definitively that there are benefits of testosterone therapy for older men…the committee recommends short-term efficacy trials to determine if there are benefits of testosterone therapy in older men.”

Apparently, at the cost of the health and possibly lives of many thousands of middle-aged and elderly men, the Institute of Medicine committee has decided that yet another trial of testosterone supplements should be conducted, a trial that will take years and be funded by taxpayers, while those very same taxpayers are suffering from the very real, and often very debilitating symptoms, of andropause-induced testosterone deficiency.

Instead of reading the Institute of Medicine’s book, the media instead chose to malign the multiple benefits of testosterone replacement and exaggerate its potential side effects. Testosterone and Aging cites numerous clinical studies showing significant anti-aging effects, but the media reported only the disparaging conclusions made by certain committee members that had little or no basis in fact.

Unlike the mainstream media, we actually read the book, which provides solid scientific evidence that aging men should seek to maintain youthful testosterone levels.