A new study shows that heavy and regular cannabis use may increase the risk of head and neck cancer.
The study examined 20 years of medical records of more than 116,000 US adults with cannabis use disorder (CUD). affect 3 out of 10 cannabis usersThe disorder is defined as problematic cannabis use that causes significant impairment or distress and is accompanied by signs of tolerance – where someone needs to take a larger amount of the drug to achieve the same high – and dependence, including withdrawal symptoms.
Compared with adults without CUD, these people were 3.5 to 5 times more likely to develop head and neck cancer, according to the new study published Thursday (Aug. 8) in the journal. JAMA OtorhinolaryngologyThese include cancers of the mouth, throat, larynx, salivary glands and Oral and pharyngeal areawhich includes the tongue, tonsils and the back of the pharynx.
“This is one of the first studies – and the largest to date – to link head and neck cancer to cannabis use,” said the lead study author. Niels Kokota head and neck surgeon at the Head and Neck Center of the University of Southern California, said in a opinion. “Recognizing this risk factor is important because head and neck cancer may be preventable if people know what behaviors increase their risk.”
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The study relied on data collected between 2004 and 2024 from TriNetX, a repository of patient data from 64 U.S. health centers. In addition to patients with CUD, the study included data from over 3.9 million people without a diagnosis of the disorder.
People with CUD were directly compared with people of the same age and gender, and researchers also took into account alcohol and tobacco use, which are leading causes of head and neck cancer.
Compared with controls, people with CUD were more likely to develop all types of head and neck cancer, except hypopharyngeal cancer, which affects the lower throat.
The study did not examine how the patients consumed cannabis—whether they smoked it or consumed edible cannabis. Therefore, it cannot say for sure whether it is the smoke that drives the cancer, since cannabis smoke contains some carcinogens similar to those in tobacco smoke. Alternatively, the active ingredients in cannabis such as THC, activate certain enzymes which can promote cancer.
“The cannabinoids themselves could be carcinogenic, and it could also be that the smoke itself could be carcinogenic,” Kokot said. told NBC News.
However, the study also has some limitations. For example, participants’ cannabis use was self-reported and the exact doses they were exposed to are unknown.
Although it is too early to say whether the link between heavy cannabis use and head and neck cancer holds over time, “the implications of the report are sobering,” wrote doctors at UC San Diego Moores Cancer Center and Xiangya Hospital in China in a Comment on the study.
It’s notable that the study’s data spanned two decades during which cannabis use became more commonplace, they wrote. If it can be confirmed that cannabis somehow promotes cancer, we might expect rates of head and neck cancers linked to the drug to rise in line with cannabis use, they concluded.
This article is for informational purposes only and does not constitute medical advice.
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