Testosterone and Prostate Cancer

Does Testosterone cause prostate cancer?

The simple answer is no. This is true for testosterone pellet therapy as well.
Many physicians continue to think that testosterone causes prostate cancer, it simply doesn’t.  In the last decade, this myth has been disproven by researchers around the world in many different studies.

In fact, low testosterone can cause prostate cancer.  There are many articles and research on this issue.  Dr. Abraham Morgantaler (a urologist from Harvard University) has proven that low testosterone is directly related to prostate cancer.

The recent article from Urology and published by the National Institute of Health makes the point clear.

In this review, we examine existing data surrounding testosterone and prostate cancer. There is significant evidence that androgens promote prostate cancer in experimental systems. However, there is no clear evidence that elevations in endogenous testosterone levels promote the development of prostate cancer in humans. As a result of experimental and historical data on the progression of prostate cancer following TRT, there has been a widespread belief that TRT will promote disease progression in prostate cancer patients. Despite these fears, there are a growing number of studies demonstrating no increase in prostate cancer incidence among men on TRT. Furthermore, in studies involving a small number of patients, there has been no discernable increase in disease progression in prostate cancer patients on TRT. While data from large, prospective, randomized, controlled trials are absent, TRT in select prostate cancer patients is likely safe. Original article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4647137/

If I have prostate cancer, can I be on Testosterone pellets?

After the diagnosis of prostate cancer, it is not recommended to be on testosterone replacement. The same goes for Benign Prostatic Hypertrophy. There have not been many studies on this for obvious reasons; A study can’t do harm to the patient for the sake of research. If the prostate and the nodes are completely removed and after 5 years there is no remission, pellets are allowed for patients that are willing to sign a high-risk waiver.

These findings are backed up by the same article referenced above. 
The abstract ends with this note. 
The use of TRT in prostate cancer patients is still considered experimental and should only be offered after well-informed shared decision making and with close monitoring.