Cannabis use linked to head and neck cancer risk

Using cannabis heavily and regularly may raise the risk of head and neck cancers, a new study finds.

The research looked at 20 years' worth of medical records from more than 116,000 U.S. adults with cannabis use disorder (CUD). Estimated to affect 3 in 10 cannabis users, the disorder is defined as problematic cannabis use that leads to significant impairment or distress and involves signs of tolerance — in which someone needs to use more of a drug to get the same high — and dependence, including withdrawal symptoms.

Compared to adults without CUD, these individuals were 3.5 to five times more likely to develop head and neck cancers, according to the new study, published Thursday (Aug. 8) in the journal JAMA Otolaryngology-Head & Neck Surgery. These include cancers of the mouth, throat, voice box, saliva glands and oropharynx, which encompasses the tongue, tonsils and back wall of the throat.

"This is one of the first studies — and the largest that we know of to date — to associate head and neck cancer with cannabis use," senior study author Dr. Niels Kokot, a head and neck surgeon at the University of Southern California Head and Neck Center, said in a statement. "The detection of this risk factor is important because head and neck cancer may be preventable once people know which behaviors increase their risk."

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The research pulled data collected between 2004 and 2024 from TriNetX, a trove of patient data from 64 U.S. Health centers. In addition to the patients with CUD, the study included data from over 3.9 million people without a diagnosis of the disorder.

The people with CUD were directly compared with people of the same age and sex, and the researchers also accounted for alcohol and tobacco use, which are major drivers of head and neck cancers.