Cannabis use is linked to a higher risk of head and neck cancers, according to a University of Southern California study.
People with cannabis dependence, known as cannabis use disorder, are 3.5 to 5 times more likely to develop head and neck cancer than those who do not use the substance, researchers found in a study published in JAMA Otolaryngology – Head & Neck Surgery.
Head and neck cancer (HNC) includes cancers of the mouth, pharynx, larynx, oropharynx (tongue and tonsils and back wall of the throat) and adjacent salivary glands.
“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,” said Dr. Niels Kokot, a head and neck surgeon at Keck Medicine of USC and senior author of the study. “The detection of this risk factor is important because head and neck cancer may be preventable once people know which behaviours increase their risk.”
Researchers in California searched 20 years of data through a health research network of 64 health-care organizations and looked at medical records for U.S. adults with and without cannabis-related disorder who had recorded outpatient hospital clinic visits and no prior history of HNC.
The group of with cannabis-related disorder included 116, 076 individuals, while the non–cannabis-related disorder group included 3, 985,286 individuals.
They tracked cancer cases from one to five years of cannabis use.
Researchers found those with cannabis use disorder had higher rates of all types of head and neck cancers, and that the prevalence of the cancer in that group was independent of other factors, such as age, gender and ethnicity.
The researchers believe cannabis use may increase the risk of HNC because it’s primarily consumed through inhalation, and they believe smoking pot may prove to be more hazardous than cigarettes.
“Cannabis smoking is typically unfiltered and involves deeper inhalation compared to tobacco,” Kokot said. “Additionally, cannabis burns at a higher temperature than tobacco, increasing the risk of cancer-causing inflammation.”