Regular marijuana usage has been linked to a higher risk of testicular cancer, researchers from the University of California have revealed.

The findings, published in Cancer, a peer-reviewed journal by the American Cancer Society, say the cancer-causing effects of marijuana on testicular cells should be assessed in decisions associated with recreational drug use, as well as when used for therapeutic purposes in male patients.

A previous study in February 2009, carried out by scientists from the Fred Hutchinson Cancer Research Center in Seattle, also suggested a link between regular marijuana usage and testicular cancer.

Testicular cancer is the most common form of cancer found in men aged 15 to 45 years. The presence of cancerous cells has increased recently and researchers think it is due to additional exposure to unidentified environmental causes.

To test whether recreational drug use contributes, Victoria Cortessis, MSPH, PhD, assistant professor of preventive medicine at the Keck School of Medicine of USC in Los Angeles, and her team examined the history of drug use in 163 young men diagnosed with testicular cancer and compared it with 292 healthy men with the same age and race characteristics.

The researchers found that men with a history of marijuana use were twice as likely to develop subtypes of testicular cancer, such as mixed germ cell tumors and non-seminoma. These subtypes generally appear more frequently in younger men and are associated with a more severe prognosis than the seminoma subtype. These results support two previous reports published in Cancer, which proposed a possible link between marijuana use and testicular cancer.

Cortessis says:

“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.”

The team also uncovered that men with a history of cocaine use had a decreased risk of both subtypes of testicular cancer. It is unknown the exact influence cocaine has on testicular cancer risk, however, authors believe the drug might kill sperm-producing germ cells.

If the predictions of the authors are correct, prevention could come at high a cost. Germ cells are not able to develop cancer if they are first destroyed but this can also damage fertility. Since this is the first study to exhibit a relationship between cocaine use and lower testicular cancer risk, further studies are needed to corroborate these results.

Written by Kelly Fitzgerald