Men with low testosterone are less likely to develop prostate cancer, scientists have found.
The discovery could lead to new methods of treatment by reducing the hormone.
Oxford scientists who looked at 19,000 men found those with the lowest testosterone levels were 20 percent less likely to get the cancer.
However, if they did get the disease, they were 65 percent more at risk of suffering an aggressive form.
One in eight men will develop prostate cancer, with approximately 46,700 cases a year.
But little is known about what causes the disease as, unlike most cancers, it does not seem to be linked to obesity, exercise, smoking or alcohol. Study co-author Professor Tim Key said: ‘This is an interesting biological finding that could help us understand how prostate cancer develops and progresses.’
Researchers believe that as prostate cancer tumours need testosterone to grow, men with lower levels are less likely to get the illness.
The study will be presented next week at a National Cancer Research Institute conference in Liverpool. Professor Malcolm Mason, of Cancer Research UK, said: ‘It’s possible that this could help unravel ways to diagnose and treat fatal prostate cancers before they can do any harm, but that’s very far down the line.’