Researchers from the University of Southern California (USC) have found a link between recreational marijuana use and an increased risk of developing subtypes of testicular cancer that tend to carry a somewhat worse prognosis.
Their study suggests that the potential cancer-causing effects of marijuana on testicular cells should be considered not only in personal decisions regarding recreational drug use, but also when marijuana and its derivatives are used for therapeutic purposes in young male patients.
Testicular cancer is the most common cancer diagnosed in young men aged between 15 to 45 years.
The malignancy is becoming more common, and researchers suspect this is due to increasing exposure to unrecognised environmental causes.
Researcher Victoria Cortessis and her colleagues looked at the self-reported history of recreational drug use in 163 young men diagnosed with testicular cancer and compared it with that of 292 healthy men of the same age and race or ethnicity.
They found that men with a history of using marijuana were twice as likely to have subtypes of testicular cancer called non-seminoma and mixed germ cell tumours.
These tumours usually occur in younger men and carry a somewhat worse prognosis than the seminoma subtype.
"We do not know what marijuana triggers in the testis that may lead to carcinogenesis, although we speculate that it may be acting through the endocannabinoid system-the cellular network that responds to the active ingredient in marijuana-since this system has been shown to be important in the formation of sperm," Cortessis said in a statement.
The researchers also discovered that men with a history of using cocaine had a reduced risk of both subtypes of testicular cancer.
This finding suggests that men with testicular cancer are not simply more willing to report a history of using recreational drugs.
While it is unknown how cocaine may influence testicular cancer risk, the authors suspect that the drug may kill sperm-producing germ cells since it has this effect on experimental animals.
The study was published in the journal 'CANCER'.
