Low Free Testosterone Concentration May Equal Low Prostate Cancer Risk
Posted: Wednesday, September 19, 2018
Although biologic evidence supports an association between testosterone concentration and prostate cancer risk, epidemiologic studies have not found data to support this claim. Eleanor L. Watts, DPhil candidate, of the University of Oxford, and colleagues recently published a study in the journal European Urology with evidence that may just indicate a link. In fact, according to their findings, men with the lowest free testosterone concentration had a 23% reduced risk of prostate cancer compared with men with higher concentrations.
“This is the largest collection of data on hormones and prostate cancer risk available and is the first large-scale prospective evidence supporting an association between low free testosterone concentrations and prostate cancer risk,” the investigators stated.
From 20 prospective studies, researchers analyzed 6,933 prostate cancer cases, diagnosed on average 6.8 years after blood collection. They also studied 12,088 controls in the Endogenous Hormones, Nutritional Biomarkers, and Prostate Cancer Collaborative Group.
They found that men in the lowest tenth of free testosterone concentration had a lower risk of overall prostate cancer (odds ratio = 0.77; P < .001) compared with men with higher concentrations. In addition, this association seemed to vary with tumor grade, with a lower risk of low-grade disease and a nonsignificantly higher risk of high-grade disease.
Variations in men in the normal range of circulating testosterone, however, present a greater challenge for the investigators. As the association of testosterone concentration and prostate cancer risk is nonlinear, researchers emphasized the need for further studies to determine whether the association is causal or due to detection bias.