Testosterone seen unrelated to prostate cancer risk

Researchers have long believed that male sex hormones, including testosterone, influence the risk of prostate cancer. However, a collaborative analysis of 18 prospective studies, published in February 2008, determined that they are not associated with prostate cancer risk.

Launched by the Endogenous Hormones and Prostate Cancer Collaborative Group, this study pooled data from 18 previous trials, the results of which had been inconsistent. Some found minor associations between some hormones and cancer, while others did not. Individually, however, those studies had limited power to determine a link.

In this new study, researchers examined data on testosterone levels in a total of 3,886 patients with prostate cancer and 6,438 healthy men. They found that men with the highest testosterone levels were just as likely to develop prostate cancer as men with the lowest. The same held true for concentrations of other sex hormones, including DHT, estradiol, and androstenedione.

The role of testosterone in prostate cancer has not been well understood. Many scientists believe that it fuels the disease because treatments that block the hormone cause tumors to shrink. Over time, however, cancers deprived of testosterone resume their growth. That knowledge, combined with the latest findings, may spur scientists to shift their focus to other risk factors.

SOURCE: Endogenous Hormones and Prostate Cancer Collaborative Group, Roddam AW, Allen NE, et al. Endogenous Sex Hormones and Prostate Cancer: A Collaborative Analysis of 18 Prospective Studies. Journal of the National Cancer Institute 2008;100:170–83. PMID: 18230794.