Study Links Marijuana Use to Testicular Cancer

Researchers in California have found a possible link between using marijuana and developing testicular cancer. Conducting a case-control study in Los Angeles County, they found that men who had testicular germ cell tumors were about twice as likely to report having ever used marijuana as men without these tumors.

Testicular cancer is expected to be diagnosed in 8,590 men in 2012. It is often highly treatable, and usually curable. More than 90% of these cancers are germ cell tumors. The rate of testicular cancer has been increasing for several decades, but experts are not sure why. The study, published online Sept. 10, 2012 in the American Cancer Society journal Cancer, speculates that environmental causes, including recreational drug use, may play a role.

In the study, 163 men diagnosed with testicular germ cell tumors and 292 men not diagnosed with the tumors were interviewed about their recreational drug use. The researchers found that men with these tumors were about twice as likely to have a history of using marijuana. Most of the increased risk was found in men with a germ cell tumor sub-type called non-seminomas. This type of tumor is harder to treat and usually occurs in men between their late teens and early 30s.

Case-control studies such as this compare a group of people with a certain disease to a group of similar people without it, to look for factors that may contribute to the disease. However, this type of study can’t prove that a factor actually causes the disease. Other types of studies are needed for this.

Study author Victoria K. Cortessis, MSPH, PhD, of the University of Southern California in Los Angeles said her team based its hypothesis on research that shows the active ingredient in marijuana may interfere with normal hormone signaling between the brain and the testicles. Cortessis and her team plan to conduct research that will look at those processes.

Cortessis said, “Three studies have now found the same specific result – a history of marijuana use associated with double the risk of non-seminoma testicular cancer. This is a more dangerous type of testicular cancer that requires chemotherapy treatment. We have to take it seriously.”

The researchers also found that men with a history of cocaine use actually had a reduced risk of testicular cancer. Cortessis speculates this might be because cocaine destroys testicular germ cells, whether they are healthy or not. Destroying the cells prevents them from becoming cancerous, but also leads to infertility because germ cells produce sperm.

Len Lichtenfeld, MD, deputy chief medical officer for the American Cancer Society cautioned that the study’s findings are preliminary, and the number of men studied was small. Lichtenfeld said, “The study is interesting, but the findings are not conclusive. More research needs to be done to form a firmer conclusion that this is a definite relationship (between marijuana use and testicular cancer risk).”

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Population-Based Case-Control Study of Recreational Drug Use and Testis Cancer Risk Confirms an Association Between Marijuana Use and Nonseminoma Risk. Published online Sept. 10, 2012 in Cancer. First author: Victoria K. Cortessis MSPH, PhD, University of Southern California, Los Angeles.

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