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Testosterone therapy in a man with prostate cancer
There is a paradox about testosterone and prostate cancer. Since the 1940s we have known that castration results in regression of prostate cancer. However, over the past decades accumulating data have shown that testosterone therapy in hypogonadal men does not cause prostate cancer development or BPH.
This paradox that the prostate is sensitive to changes in serum testosterone at low concentrations but becomes insensitive to changes at higher testosterone concentrations is explained by the "saturation model". The "saturation model" postulates that there is a threshold beyond which increasing androgen concentrations reach a limit (the saturation point) beyond which there is no further ability to induce androgen-driven changes in prostate tissue growth.
However, there are reasons to be cautious when giving testosterone therapy to patients with prostate cancer. Prostate cancer cells are dynamic and can change over time and adapt to changes in their microenvironment. These changes occur during conditions of low testosterone concentrations, and include alteration in androgen receptor activation leading to development of more aggressive prostate cancer types, stimulation by returning testosterone levels to normal range or reversal by returning testosterone levels to normal range. Problem is that it cannot be readily predicted in which direction the changes will lead.
Dr. Goldenberg presents data from his study that investigated the effects of testosterone therapy in men with treated and untreated prostate cancer.1 Results showed that testosterone therapy for up to 55 months in men after radical prostatectomy or radiation, and in men on active surveillance, in most cases does not cause prostate cancer recurrence or worsening. The risk of prostate cancer recurrence appears to be lower after radical prostatectomy than after radiation. The conclusion from this study is that testosterone therapy in men with untreated low risk prostate cancer or treated prostate cancer of all risk grades is not associated with negative outcomes.1
Larry Goldenberg, CM, OBC, MD Jarislowski Chair, Department of Urologic Sciences, UBC Chairman, Canadian Men's Health Foundation