A recent investigation indicates that cannabis, the most widely used illegal substance globally, is linked to a higher risk of developing head and neck cancer.
A study conducted by the USC Head and Neck Center, part of Keck Medicine of USC and the USC Caruso Department of Otolaryngology — Head and Neck Surgery, suggests that cannabis, the most widely used illegal substance globally, is linked to a higher incidence of head and neck cancer.
A comprehensive, multicenter study published in JAMA Otolaryngology — Head & Neck Surgery found that adults with cannabis dependence, also referred to as cannabis use disorder, are 3.5 to 5 times more likely to develop head and neck cancer compared to those who do not use cannabis.
“This is one of the earliest studies — and the largest so far — to correlate head and neck cancer with cannabis consumption,” stated Niels Kokot, MD, a head and neck surgeon at the USC Head and Neck Center and the lead author of the study. “Identifying this risk factor is crucial as head and neck cancer could potentially be preventable once individuals are aware of the behaviors that elevate their risk.”
Kokot is also a professor of otolaryngology — head and neck surgery at the Keck School of Medicine of USC.
Head and neck cancer, which ranks as the sixth most common cancer in the world, encompasses various cancers, including those of the mouth, pharynx, larynx, oropharynx (tongue, tonsils, and back wall of the throat), and nearby salivary glands.
Researchers, including lead study author Tyler Gallagher, an MD/MPH candidate at the Keck School, found that individuals with cannabis use disorder exhibited elevated rates of all forms of head and neck cancers. Importantly, they noted that the occurrence of head and neck cancer among those with cannabis use disorder was independent of other factors such as age, gender, and ethnicity. Use of alcohol and tobacco, which are known risk factors for head and neck cancer, did not influence their findings either.
Kokot and the team theorize that the primary reason behind the higher risk of head and neck cancer related to cannabis is the harmful effects of smoke. Cannabis is mainly consumed by inhalation (though the study did not differentiate among consumption methods). Previous research has indicated that tobacco smoke contains various chemicals that can cause DNA damage and trigger inflammation, which can lead to cancer if not addressed. They propose that cannabis smoke might inflict similar damage.
Indeed, Kokot speculates that cannabis smoke may even be more damaging than tobacco smoke.
“Smoking cannabis typically involves unfiltered inhalation and deeper draws compared to tobacco,” he explained. “Moreover, cannabis burns at a higher temperature than tobacco, which could enhance the risk of inflammation that could lead to cancer.”
Kokot hopes for more research into the relationship between cannabis and head and neck cancer. In the meantime, he aims for this study to encourage individuals to make better-informed decisions and promote awareness regarding the connection between cannabis use and head and neck cancer.
To arrive at their conclusions, the researchers analyzed two decades’ worth of data from a health research network encompassing 64 healthcare organizations and representing over 90 million individuals. They tracked cancer incidences linked to one to five years of cannabis use.
