Under the age of 50, the chance of a man getting prostate cancer is about 1 in 500: https://www.pcf.org/about-prostate-cancer/what-is-prostate-cancer/prostate-cancer-survival-rates/.
As his testosterone declines, markedly around this age, the chance skyrockets to 1 in 54. The next decade, as testosterone declines further, risk jumps to 1 in 19. Again, at the next decade, it nearly doubles to 1 in 11. And now, epidemiologists and statisticians agree that into old age the risk approaches 100%. That is, if you live long enough, as testosterone declines toward zero, risk rises to assurance. As a man, if you die of old age, you will die with prostate cancer. Not OF. But WITH. 100%.
Perhaps even more interesting is that prostate cancer incidence is highest in Europe, then North America, then Australia: https://www.frontiersin.org/articles/10.3389/fpubh.2022.811044/full
And of absolutely no surprise, the three regions where we’ve seen the most dramatic drop in testosterone levels over the past decades are these same places where prostate cancer incidence is highest. In fact, the RATE (1% per year: https://www.reuters.com/article/health-testosterone-levels-dc/mens-testosterone-levels-declined-in-last-20-years-idUKKIM16976320061031 ) of drop in population testosterone looks an awful lot like the RATE (3% per year: https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html) of increase in prostate cancer incidence.
To be clear, the prevalence of prostate cancer is highest among males with low and/or declining testosterone. The phenomenon essentially didn’t exist in young men, until a society-wide trend developed starting around 1990, wherein a 2% per year increase in prostate cancer risk among 15-40 year olds came to be: https://pubmed.ncbi.nlm.nih.gov/31553489/ . With no need for conspiracy thinking, this dovetails extremely tightly with the decline in testosterone among the same populace during the same timeframe.
Moreover, recent studies on men who are taking synthetic testosterone replacement therapy find they they have a lower risk of aggressive prostate cancer: https://ascopubs.org/doi/full/10.1200/JCO.2016.69.5304
Looking at 150,000 men on testosterone replacement therapy determined that risk of prostate cancer did not rise even with higher dosing: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199194
A study on 17,049 men indicated that the higher the testosterone and androgens, the LOWER the risk of all aggressive cancers, not just prostate cancer: https://aacrjournals.org/cebp/article/15/1/86/258197/Circulating-Steroid-Hormones-and-the-Risk-of
Testosterone protects AGAINST prostate cancer, and a whole lot more.