Some of coffee's components can have beneficial effects
Drinking coffee could help to cut the risk of advanced prostate cancer, a US study suggests.
It found the heaviest consumers had a 60% lower risk of aggressive tumours than men who did not drink any coffee.
Coffee has an effect on the way the body breaks down sugar and also on sex hormone levels - both of which have been linked to prostate cancer.
The Harvard Medical School study was presented to an American Association for Cancer Research conference.
Researcher Dr Kathryn Wilson said: "Very few lifestyle factors have been consistently associated with prostate cancer risk, especially with risk of aggressive disease, so it would be very exciting if this association is confirmed in other studies."
The researchers are unsure which components of coffee might have a positive effect.
However, it is known to contain many biologically active compounds, such as minerals and antioxidants, which limit damage to the tissues caused by the release of energy in cells.
The researchers documented the coffee intake of nearly 50,000 men every four years from 1986 to 2006.
They stress that more work is needed before any firm conclusion can be drawn about the beneficial effects of coffee.
But, at the very least, Dr Wilson said: "Our results do suggest there is no reason to stop drinking coffee out of any concern about prostate cancer."
Helen Rippon, of The Prostate Cancer Charity, said previous research on the effect of caffeinated drinks on prostate cancer had produced mixed results.
She said the latest study suggested drinking coffee might have a beneficial effect but more work was needed to draw firm conclusions.
She said: "We would not recommend that men cultivate a heavy coffee drinking habit on the back of this research, not least because a high caffeine intake can cause other health problems.
"However, men who already enjoy a regular cup of coffee should be reassured that they do not need to give this up for the sake of their prostate."
Jessica Harris, of the charity Cancer Research UK, said: "A number of other studies looking at coffee and prostate cancer have found that drinking coffee does not affect the risk of prostate cancer."