Similarly, no hormone level combination -- such as a very high concentration of one sex hormone and a very low concentration of another -- was associated with prostate cancer risk.
In an accompanying editorial, co-author Dr. Paul A. Godley, an associate professor of medicine at the University of North Carolina School of Medicine, said the "impressive" findings could push prostate cancer research in a new direction.
"Researchers should redirect their attention toward investigations of potentially modifiable nutritional, lifestyle or environmental risk factors," he suggested, rather than target unchangeable factors -- such as blood hormone levels -- that do not appear to affect risk.
But, Dr. Peter T. Scardino, chairman of the department of surgery at Memorial Sloan-Kettering Cancer Center in New York City, cautioned that it would be wrong to conclude that male hormones have nothing to do with prostate cancer.
"This study asks if the amount of male or female hormones in your bloodstream can predict whether you will get prostate cancer, and the answer is no," he said. "But the prostate is like a sponge for hormones that sucks them out of circulation and converts them to even more powerful forms that can go to work in the prostate. So blood hormone levels may not have any connection with the amount of hormone in the prostate gland itself.
"The point is," he added, "I would not want people to think that altering the male hormone environment in the prostate has no effect. It certainly will. So if you take drugs like finestaride to shrink your prostate to urinate better, or Propecia to prevent balding, these drugs are working directly on hormone levels in the prostate, not the bloodstream. And these drugs work very well."
More information
For additional information on prostate cancer risk, visit the American Cancer Society.
