Is Testosterone A Cause of Prostate Cancer?
Here’s a trick question: who mostly get prostate cancer: young men or old men?
The answer is of course that, as with most cancers, older men are much more likely than young men to get prostate cancer.
Then why is it that testosterone has been feared as a cause of prostate cancer?
If testosterone caused prostate cancer, we should see it much more often in young men, who have levels of testosterone peaking around age 30.
Testosterone levels in men peak around age 30, then decline 1 to 3% per year from then on. As a man gets older, and his testosterone level goes down, his risk of prostate cancer increases.
How common is prostate cancer?
In the U.S., about 11% of men will develop prostate cancer at some time in their life.
Prostate cancer is the second most common cancer in men, after lung cancer; it is the 3rd highest cause of cancer deaths in men (after lung cancer and colon cancer).
According to the National Cancer Institute, 9 out of 10 men with prostate cancer get diagnosed with the disease either limited to the prostate or with spread to nearby lymph nodes. The 5-year survival for these men is 100%. Because most men are diagnosed in the early stages of this cancer, the overall 5-year survival rate is 98.2%.
Reference: https://seer.cancer.gov/statfacts/html/prost.html
How does testosterone affect prostate cancer?
Until recently, testosterone was thought to fuel prostate cancer cell growth. It was compared to throwing gasoline onto a fire. The current thinking is called the “saturation model”, which is like giving water to a thirsty plant – at first, the plant will grow but only up to a limit.
Dr. Abraham Morgentaler, in his book Testosterone For Life, states, “My real concern now is that men with low T are at an increased risk of already having prostate cancer.” His analysis of the data up to 2009 included these conclusions: low blood levels of testosterone, which should, in theory, be protective against prostate cancer, in fact, were associated with a higher risk of this cancer; high blood levels of testosterone do not increase the risk of prostate cancer (even men at high risk for it).
So what does cause prostate cancer?
Normal prostate cells have an inactive (suppressed) gene for an enzyme called aromatase, which causes the production of estrogen. (This is the enzyme that is blocked by one type of breast cancer drug, the aromatase inhibitors since it blocks the formation of estrogen.)
Latest thinking about how prostate cancer begins is that this gene becomes active and causes high local levels of estrogen in the prostate. An excellent detailed discussion of this is in The New Testosterone Treatment: How You and Your Doctor Can Fight Breast Cancer, Prostate Cancer, and Alzheimer’s by Dr. Edward Friedman (2013).
A 2015 meta-analysis (which summarizes and analyzes the results from 18 published studies on testosterone levels and prostate cancer) confirms that “testosterone, whether occurring naturally or taken as replacement therapy, does not cause prostate cancer or spur increases in prostate-specific antigen (PSA) levels in men”.
What does this mean for men?
As our lifespan increases, we want our health-span to increase as well. Hormone therapy for the quality of life is no longer a “pact with the devil”, where you live better but increase your health risks. In fact, with prostate cancer, the opposite seems to be true.
What these findings add up to is that men with relatively low testosterone levels who are feeling fatigue, depression, decreased sexual function, loss of muscle mass, weight gain, memory loss, irritability (and the list goes on), do not have to fear that supplementing with testosterone will increase their risk of prostate cancer.
Please note: The material in these articles, provided by Dr. Liz Lyster, is designed to provide informative and current information as of the date of the posts. The articles should not be considered, nor are they intended to constitute medical advice. For information on your particular circumstances, please contact us.