Cannabis users are 3.5 to five times more likely to develop head and neck cancers, a recent Los Angeles-based Keck Medicine of USC study found.
The study, published Aug. 8 in JAMA Otolaryngology-Head & Neck Surgery, drew from 20 years of data from 64 healthcare organizations. Researchers examined medical records of adults with and without cannabis-related disorders who had outpatient hospital clinic visits and no prior history of head and neck cancers. The study compared records from 116,076 individuals with cannabis-related disorder, and more than 3.9 million individuals without cannabis disorder. The data was also stratified by demographic characteristics, alcohol-related disorders and tobacco use.
The study found those with cannabis-related disorders had higher risk of any head and neck cancer compared with the control group. Cannabis-related disorder was connected to a highest risk of oral, oropharyngeal and laryngeal cancers.
The results were consistent across younger and older age groups. Alcohol and tobacco use did not play a role in the findings.
"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," lead author Niels Kokot, MD, a head and neck surgeon with the USC Head and Neck Center, said in an Aug. 8 system news release. "The detection of this risk factor is important because head and neck cancer may be preventable once people know which behaviors increase their risk."
About three in 10 cannabis users have cannabis-related disorder — defined as problematic cannabis use that leads to impairment or distress, and shows signs of tolerance and dependence.