Another Problem with Pot – Cancer of the Testis

Only 6 weeks ago I posted a report of the increased risk of lung cancer in marijuana users. Now a study described in the journal Cancer brings data on the risks of another dangerous effect of pot smoking – cancer of the testis.

Researchers at the Fred Hutchinson Cancer Research Centre in Seattle examined the medical records of 369 men with a diagnosis of testicular cancer, whose ages ranged from 18 to 44. The subjects were interviewed about their lifetime marijuana use. As controls, 979 men living in the same area during the same period were interviewed.

The analyses showed that men with testicular germ cell tumors, which account for 40% of all testicular tumors, had a 70% increased likelihood of this tumor type if they were using marijuana at the time of diagnosis, when compared to the controls. The risk was particularly increased – to about twice that of those men who never smoked marijuana – for men who used the drug at least weekly and/or who had long-term exposure beginning in adolescence.

The receptors which bind with the active substance found in cannabis are known to be present in the brain, but they are also found in the testes. It’s proposed that these receptors protect against certain forms of cancer. So, when a man smokes a joint, the cannabis passes into the testes and inhibits their protective effect.

The incidence of this type of testis cancer (which includes the better-known subtype called seminoma) is increasing at a rate of 3% to 6% a year. And the use of stronger marijuana is also increasing, in the same geographical areas as the testicular tumor increase. So marijuana probably isn’t so harmless . . .