A new study suggests that men with a daily marijuana-smoking habit could have an increased risk of developing testicular cancer.

The study, published last week in JAMA Network Open, found that men who regularly smoked marijuana for more than 10 years had an estimated 36 percent increased risk for testicular cancer — compared to men who had never smoked pot.

Researchers analyzed 25 studies that assessed the link between marijuana use and the risk of developing lung, head and neck, testicular and other cancers. They found that regular marijuana use contributed to men developing testicular germ cell tumors, although the strength of the evidence was “low.”

A file image shows a man smoking a joint during a march demanding the legalization of marijuana in Sao Paulo, Brazil, on June 1, 2019. (Photo credit: MIGUEL SCHINCARIOL/AFP via Getty Images)

Like cigarettes, smoking marijuana releases carcinogens, according to the American Lung Association — substances that can increase a person’s risk of developing cancer.

“Low-strength evidence suggests that smoking marijuana is associated with developing TGCT,” researchers concluded in the study. However, any association between regular marijuana use and other cancers remained unclear.


The study authors said the findings were notable as marijuana usage has increased in the United States with vaping and edibles becoming more popular, particularly in states with legalized recreational use and among adolescents.

“Most of the studies included in the present systematic review and meta-analysis are not recent, and smoking was the near-universal form of exposure,” the authors noted.

The study authors added that longer-term studies of marijuana-only smokers would improve the understanding of marijuana’s association with lung, oral and other cancers.

An estimated 9,560 men in the U.S. will be diagnosed with testicular cancer this year, according to the American Society of Clinical Oncology. About 1 out of 250 men and boys will be diagnosed with the disease during their lifetime.

The average age of diagnosis is 33 but can occur at any age. Medical experts say an enlarged testicle or a small lump or area of hardness are typically the first signs of testicular cancer — and should be evaluated by a doctor as soon as possible.

This story was reported from Cincinnati.