Dr. C. Joseph Bennett, Navigating Cancer, 11/13/12

-A A +A

Marijuana use linked to testicular cancer

By Dr. C. Joseph Bennett

In the recent elections, several states legalized the use of recreational marijuana. Other states have already moved to legalize the medical use of marijuana.

The trend seems to show that many Americans view marijuana as a recreational drug, and that is should be legal.

There is, however, data available that shows a possible link to testicular cancer that any potential user should be aware of. 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 percent of these cancers are called 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 this study, 163 men diagnosed with testicular germ cell tumors and 292 men not diagnosed with the tumors were interviewed about their recreational drug use. This means that this was a retrospective study, one that asks people about their habits and social life after they have been diagnosed.

Researchers found 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.

While this study is interesting, it must also be taken with a grain of salt. 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. But this kind of study can lead to the creation of prospective studies that begin now, and follow people over years or decades to see if habits lead to a higher cancer risk.

What is the possible link between marijuana and testicular cancer? Research has shown that the active ingredient in marijuana may interfere with normal hormone signaling between the brain and the testicles.

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, and therefore 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. Researchers speculate 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.

Again, take this study as a possible link to testicular cancer, but at the same time have a little caution secondary to the fact that the study’s findings are preliminary, and the number of men studied was small.

Yes, 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.

Dr. C. Joseph Bennett is a board-certified radiation oncologist and a member of the Citrus County Unit of the American Cancer Society. Watch “Navigating Cancer” on WYKE TV at 7:30 p.m. Tuesdays and at 10 a.m. Thursdays. If you have any suggestions for topics, or have any questions, contact him at 522 N. Lecanto Highway, Lecanto, FL 34461, or email cjbennett@rboi.com. ­