Testosterone and Prostate Cancer: Revisiting Old Paradigms
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CONTEXT: Androgens are vital for growth and maintenance of the prostate; however, the notion that pathologic prostate growth, benign or malignant, can be stimulated by androgens is a commonly held belief without scientific basis. Therefore, the current prostatic guidelines for testosterone therapy (TT) appear to be overly restrictive and should be reexamined. OBJECTIVE: To review the literature addressing the possible relationship between testosterone and prostate cancer (PCa) and to summarize the main aspects of this issue. EVIDENCE ACQUISITION: A Medline search was conducted to identify original articles, review articles, and editorials addressing the relationship between testosterone and the risk of PCa development, as well as the impact of TT on PCa development and its natural history in men believed to be cured by surgery or radiation. EVIDENCE SYNTHESIS: Serum androgen levels, within a broad range, are not associated with PCa risk. Conversely, at time of PCa diagnosis, low rather than high serum testosterone levels have been found to be associated with advanced or high-grade disease. The available evidence indicates that TT neither increases the risk of PCa diagnosis nor affects the natural history of PCa in men who have undergone definitive treatment without residual disease. These findings can be explained with the saturation model (which states that prostatic homeostasis is maintained by a relatively low level of androgenic stimulation) and with the observation that exogenous testosterone administration does not significantly increase intraprostatic androgen levels in hypogonadal men. It must, however, be recognized that the literature remains limited regarding the effect of TT on PCa risk. Nonetheless, the current European Association of Urology guidelines state that in hypogonadal men who were successfully treated for PCa, TT can be considered after a prudent interval. CONCLUSIONS: Although no controlled studies have yet been performed and there is a paucity of long-term data, the available literature strongly suggests that TT neither increases the risk of PCa diagnosis in normal men nor causes cancer recurrence in men who were successfully treated for PCa. Large prospective studies addressing the long-term effect of TT are needed to either refute or corroborate these hypotheses.
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