But no prostate cancer by high testosterone levels
In a new study there was no relationship between androgens and prostate cancer risk. Only with decreased testosterone levels, it was slightly lower, but took at normal levels not to.The most important of the male sex hormones ( androgens ) is testosterone . This is converted in the cells in the strongest androgen DHT (dihydrotestosterone, more on the subject see sex hormones ).
In advanced prostate cancer, androgen deprivation can inhibit the growth of malignant cells (see hormonal therapy ). Therefore, it was assumed that androgens also contribute to the development of prostate cancer (androgen hypothesis; see also causes of prostate cancer ).Some earlier studies saying that a low androgen levels the risk for prostate cancer increases, especially for an aggressive tumor. In other studies, however, found no association or even the opposite. Possible reasons for these conflicting results are numerous, for example, that only very low levels stimulate the prostate growth and an excess of androgens has no additional effect (saturation model).
Reasons for the study and implementation
To determine whether androgens (male sex hormones) affect the risk of prostate cancer, now an earlier U.S. study was re-evaluated (REDUCE, published in 2004). In this descriptive study was to check whether a particular drug reduces the risk of prostate cancer. To this end, all the participants, among other things, the levels of were PSA and androgens (testosterone and DHT) and determined after 2 and 4 years, a prostate biopsy performed (the latter minimized the possible errors that a tumor is not detected because no biopsy is done). The REDUCE study included comparing men with one who did not receive the drug (placebo group). Of these well-four thousand men, a large part could be included in the present analysis.
Results and assessment
Every fourth man (819 of 3255) was discovered in the course of the four-year study, prostate cancer, which in turn had only good one in four (27.8%) had a high-grade tumor ( Gleason score of 7). Only at reduced testosterone levels (less than 10 nmol / l), the prostate cancer risk increased with the mirror up to a maximum value. In normal testosterone levels, this increase continued but does not further proceed. However, the rate of the tumors in both cases was found almost the same (at a lower limit of, for example, 7 nmol / L, they have probably differences). There is no clear relationship between DHT levels and prostate cancer risk as well as between the two androgens and the Gleason score of the tumors was discovered.
Earlier investigations implicating low androgen levels increase the risk for prostate cancer, especially for a high-grade form, were not confirmed. However, this could also be that men were excluded with a previously positive biopsy from the REDUCE trial. A statement on the risk at very low levels (eg, after castration ) was not possible due to lack of data.
Men with the lowest testosterone levels had the lowest risk of prostate cancer. It increased with the mirror up to a "saturation point" and then remained the same. This suggests that the saturation model, which describes the promotion of prostate growth by androgens, also applies here. Why DHT did not affect the risk as well, however, is unclear. Despite some limitations, the results of this study support the statements made by other studies.
Conclusion of the authors
In the placebo arm of the REDUCE study, prostate cancer risk and tumor grade were independent of the output levels of testosterone and DHT. The fact that the lowest testosterone levels were associated with the lowest risk of cancer, talk to a saturation model, but must be confirmed in further studies.Note: This study provides a contribution to the discussion of androgens (mainly testosterone) as a trigger of prostate cancer. The principle of androgen deprivation for treatment of a (usually advanced) prostate cancer is not affected and remains fully applicable (see hormone therapy ).
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