One of the most commonly cited side effects for hormone replacement therapy as a cure to low testosterone in men is an increased risk of prostate cancer. However, much like with the Million Woman Study that linked HRT and breast cancer, the evidence corroborating this belief is dated and likely false. In fact, according to some modern research, low testosterone is actually a risk factor FOR types of male cancer.
The origins of the theory that testosterone replacement increased the risk of prostate cancer go back to research done at the University of Chicago in the 1940s by a group led by urologist Charles Huggins. Based on experiments performed first on dogs and then on humans, Huggins’ group concluded that prostate cancer was androgen dependent – when testosterone levels were high, the cancer worsened, but when the levels were lowered, the cancer shrank. Huggins’ theory led to surgical castration – removal of the testicles – becoming the standard treatment for prostate cancer because of the resultant drop in testosterone. Huggins was awarded a Nobel Prize in 1966 for these contributions to medical research.
Huggins’ findings led scientists and doctors to believe for many years that testosterone levels and prostate cancer occurrence were linked, despite the fact that his experiments didn’t test nor prove this and were limited to small numbers of test subjects. This caused medical professionals to be skeptical of hormone replacement therapy, fearing that it could lead to the development of prostate cancer. Many shied away from prescribing HRT, despite its benefits.
As time went on, more research was done, and studies showed that men with low testosterone seemed to develop prostate cancer at a higher than average rate, and that testosterone only caused progression of cancer of the prostate in men who had been castrated, and not in men who still produced testosterone naturally. The supposed link between testosterone and prostate cancer had to be reexamined.
Eventually, the medical community began to change its tune as it was presented with new evidence. A number of studies done in the 2000s, including ones published by the New England Journal of Medicine and the Mayo Clinic, showed no correlation between elevated testosterone levels and cancer of the prostate. Separate studies done by Abraham Morgentaler, a leading doctor in the field, showed that raising the levels of testosterone in men already diagnosed with prostate cancer caused no further progression of the disease, and that men in the lower range of testosterone levels are actually more at risk of developing prostate cancer than men with higher amounts. It’s now become clear that the relationship between testosterone and cancer of the prostate was misunderstood for much of the 20th century, and that hormone replacement as a means of supplementing low testosterone levels in men won’t cause the disease.
So if you’re a man who suspects he may have low testosterone, and are considering hormone replacement therapy, you can rest easy. HRT won’t give you prostate cancer; in fact, it might help prevent it.