Here’s some sobering news for stoners.
Frequent, heavy pot smoking may raise the risk for head and neck cancers (HNCs), a new University of Southern California study finds.
Marijuana users are 3.5 to 5 times more likely to develop head and neck cancers than those who pass on joints, according to research published Thursday in JAMA Otolaryngology–Head & Neck Surgery.
“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 with the USC Head and Neck Center 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 behaviors increase their risk.”
HNCs, which include throat, thyroid, salivary, nasal and sinus cancers, account for nearly 3% of cancer diagnoses and more than 1.5% of cancer deaths in the US.
Meanwhile, marijuana is the most prevalent illicit substance domestically and internationally, with usage steadily increasing in the last decade.
HNCs have been previously linked to excess alcohol consumption and cigarette smoking, and people who do both are at greater risk of developing these cancers than those who consume either independently.
The USC researchers noted that studies that have explored the association between cannabis and HNC risk have produced inconsistent results. For their research, they analyzed data from 116,000 pot smokers.
They found that pot may prove more hazardous than cigarettes.
Cannabis contains carcinogens similar to those in tobacco products, but smoking pot may lead to more inflammation in the body.
“Compared with smoking tobacco, smoking cannabis may be even more pro-inflammatory. Cannabis smoking is typically unfiltered and consumed through deeper breaths than tobacco,” they wrote in their findings. “Additionally, cannabis burns at a higher temperature than tobacco, increasing the risk of inflammatory injury.”
While the evidence suggests a relationship between HNCs and cannabis, researchers admit their study has limitations. Among these is a lack of information regarding dosage, frequency and method of marijuana use.
Northwell Health’s Dr. Michael Blasco, the director of head and neck oncology and reconstruction at Staten Island University Hospital, said while the study highlights a potential link between cannabis and HNCs, it still leaves questions, particularly about methodology.
“Is there a difference in patients that, for example, use edibles or gummies or brownies versus people who smoke it? And if they do smoke it, how are they smoking it? Or are they vaping?” wondered Blasco, who was not involved in the research.
“I would say, in general, we know that there’s a link between head and neck cancer now in cannabis, and we don’t know what the safe threshold is and or if there even is one,” he added. “And we don’t know if there’s a safe method of using it.”
The USC researchers say future studies that explore this association should include “more thorough data on cannabis use.”
