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from http://www.news.com.au/story/0,27574,25032892-23109,00.html

Study links smoking cannabis to testicular cancer

YOUNG men who smoke marijuana are more likely to develop an aggressive form of testicular cancer than those who have never tried the drug, a study has found.

The US research was the first to find evidence of a link between cannabis and testicular cancer.

It found smoking the drug at least once a week, or using it regularly from adolescence, doubled the risk of a fast-growing form of the disease called nonseminoma, which tends to strike men in their 20s and 30s.

The study, by scientists at the Fred Hutchinson Cancer Research Center in Seattle and published in the journal Cancer, asked 369 testicular cancer patients if they had a history of marijuana use.

A further 979 healthy men were asked about their use of the drug.

Being an existing cannabis user raised the risk of cancer by 70 per cent, while men who had used the drug regularly from puberty were twice as likely to develop the disease than those who had not used it.

Epidemiologist and study author Stephen Schwartz said: "Our study is not the first to suggest that some aspect of a man's lifestyle or environment is a risk factor for testicular cancer, but it is the first that has looked at marijuana use".

Researchers suggest cannabis may interfere with a man's natural production of a substance thought to protect against tumours.