News

Cannabis may increase chances of head and neck cancer

Published on August 16, 2024 by David Wylie

Photo: Adobe stock/the oz.

Cannabis has not generally been linked as a cause of cancer. However, a new study has found some evidence that chronic use of cannabis can be associated with increased risk of head and neck cancer.

US researchers from the University of Southern California, University of California, and Stanford University conducted a cohort study that included more than four million people—including more than 115,000 with cannabis use disorder. They found those with cannabis use disorder may be at an increased risk of any head and neck cancer, as well as oral, oropharyngeal, nasopharyngeal, salivary gland, and laryngeal cancer, compared with a group of matched individuals.

“Cannabis is the most commonly used illicit substance worldwide Whether cannabis use is associated with head and neck cancer (HNC) is unclear,” says the summary posted on Jama Network.

“Further studies are required to further explore the strength and potential mechanisms of this association.”

Method to the study

The large multi-centre cohort study used clinical records from a database that included 20 years of data (through April 2024) from 64 health care organizations. The database was searched for medical records for US adults with, and without, cannabis-related disorder who had recorded outpatient hospital clinic visits and no prior history of HNC.

Researchers matched for demographic characteristics, alcohol-related disorders, and tobacco use. Relative risks were then calculated to explore risk of HNC, including HNC subsites. The analysis was repeated among those younger than 60 years and 60 years or older.

Findings of the study

Researchers found that the 116,076 people who regularly used cannabis had a higher HNC diagnosis rate than those who did not. That group consisted of 44.5% of women and had a mean age of 46.4.

For comparison, the non-cannabis cohort included 3,985,286 individuals, with 54.5% women and a mean age of 60.8.

“The rate of new HNC diagnosis in all sites was higher in the cannabis-related disorder cohort,” says the study, including oral, oropharyngeal, and laryngeal cancer.