Does Testosterone Cause Cancer?
In 2012 I was a first year urology resident rotating at the Veterans Affairs hospital. The chief of urology there, Dr. Borges, was a quiet, serious, and very private man. I’m not sure he knew what to do with me—a chatty, inquisitive, and very new doctor.
Though quiet, Dr. Borges was a magnificent educator. He would spend hours teaching medical students the basics of urology and sitting with the urology trainees to review surgical techniques on one of his many yellow legal pads.
I’ll never forget the day he handed me a pre-highlighted article that he read in a urology magazine. That small act changed the course of my entire career.
“Rubin,” he said. “Read this article. This guy Dr. Abe Morgentaler at Harvard has an interesting theory about testosterone and prostate cancer.”
Until that point doctors were taught that testosterone causes prostate cancer. When a man presented with metastatic prostate cancer the treatment was (and still is) surgical or medical castration to starve the cancer cells. So, the theory we were taught went, high testosterone causes prostate cancer and low testosterone must be protective against cancer.
But Dr. Morgentaler questioned this theory. He went back to the original sources from the 1940s—data from Nobel Prize winner Dr. Charles Huggins (the only urologist who has won a Nobel Prize so far).
In 1940 Huggins wrote that prostate cancer is activated by testosterone injections. But the data he published was based on only two men, one of whom was already castrated, and the cancer marker he used was ultimately found unreliable.
Medical dogma—that testosterone causes prostate cancer—was based on bad science. Yet it is still widely believed by doctors and patients.
While it’s true that lowering testosterone levels can slow the growth of metastatic prostate cancer, adding testosterone doesn't necessarily have the inverse effect. It's not quite that simple.
Dr. Morgentaler and his close colleague, Dr. Abdul Traish, pioneered what is now called the saturation model.
The idea of the saturation model is this: The prostate has a finite number of hormone receptors. Once those receptors are saturated, additional hormone does not increase growth.
Morgentaler uses the example of a house plant.
If you deprive a house plant of water, it will shrivel up and die. But once you add enough water to keep the plant healthy, any additional water will not change the growth trajectory of the plant. A house plant will not become a redwood tree no matter how much water you give it.
Further research found that the saturation model can be shown in real numbers. At a testosterone above 250 ng/dL there are no changes to the hormone receptors in the prostate tissue.
So why is this important? Because low testosterone can lead to real quality of life symptoms like low libido, erectile dysfunction, and fatigue. There are studies that show long term use of testosterone in men can help keep weight off, keep bones strong, and even prevent or improve diabetes.
But most of our medical training taught us that testosterone causes prostate cancer in men, and estrogen causes breast cancer in women. Neither of which is true nor a black and white issue, but fear and politics seem to prevail.
In 2012 I learned about the saturation model from Dr. Borges. That same year I presented the concept in a lecture to my urology department at Georgetown, and I attended a national urology conference and watched Dr. Morgentaler lecture in a small room. I watched verbal tomatoes get thrown at him by the urology community who did not yet understand the data.
Dr. Morgentaler didn’t budge. The data was the data. Year after year he continued to discuss the saturation model. It took 10 years, but in 2022 he gave a keynote lecture at the same urology conference to thousands of people about dignity in medicine and how quality of life is essential when treating patients. The urology community has done a complete 180 on their views of testosterone and prostate cancer. In fact, testosterone guidelines published in 2018 say: “Clinicians should inform patients of the absence of evidence linking testosterone therapy to the development of prostate cancer.”
Dr. Morgentaler has been a hero of mine since 2012.
Fast forward to 2023 and my brain exploded when Dr. Morgentaler invited me to be a faculty member for his Harvard Continuing Education Course on Testosterone Therapy and Sexual Dysfunction. This was the first time the course has included information on testosterone in women.
As I listened to Dr. Morgentaler and Dr. Traish teach the saturation model, ten years after I first learned about it, I was filled with the same excitement and passion. We still have a lot of work to do researching and advocating for evidence based sexual medicine care, and I'm so thrilled to be a part of the conversation.