Study: Marijuana use linked to higher risk of head and neck cancer

Here is some sobering news about the strike.

Frequent and heavy smoking may increase the risk of head and neck cancer, a new study from the University of Southern California finds.

Marijuana users are 3.5 to 5 times more likely to develop those cancers, known as HNC, than key smokers, according to research published Thursday in JAMA Otolaryngology – Head & Neck Surgery.

“This is one of the first studies — and the largest we know of to date — to link head and neck cancer to cannabis use,” said Dr. Niels Kokot, a head and neck surgeon at Keck Medicine of USC and senior author of the study. “Discovering this risk factor is important because head and neck cancer can be prevented once people know what behaviors increase their risk.”

HNCs, which include cancers of the oral and nasal cavities, pharynx, larynx, salivary glands, and thyroid, account for nearly 3% of cancer diagnoses and more than 1.5% of cancer deaths in the US.

Meanwhile, marijuana is the “most widely used illicit substance worldwide,” according to the study, with use steadily increasing over the past decade.

HNCs have previously been linked to excessive alcohol consumption and smoking, and people who do both are at greater risk of developing these cancers than those who only drink or only smoke.

The USC researchers noted that studies that have explored the link between cannabis and HNC risk have produced inconsistent results.

For their research, they compared the medical records of 116,000 people, divided between marijuana users who had reported to a health professional that they were addicted to pot and non-users with similar health characteristics. USC researchers analyzed 20 years of these medical records.

They found that pot may be more dangerous than cigarettes in terms of HRCs, even though cannabis smoke contains carcinogens similar to those found in tobacco products.

“Compared to smoking, smoking cannabis may be even more pro-inflammatory. “Smoking cannabis is usually unfiltered and is consumed through deeper inhalations than tobacco,” the study authors wrote. “In addition, cannabis burns at a higher temperature than tobacco, increasing the risk of inflammatory injury.”

While the evidence suggests a relationship between HNCs and cannabis, the researchers acknowledge that their study has limitations. Among them is the lack of information about the dosage, frequency and manner of use of marijuana.

Dr. Northwell Health’s Michael Blasco, director of head and neck oncology and reconstruction at Staten Island University Hospital, said he has questions about the study.

“Is there a difference in patients who, for example, use food or gum or brownies versus people who drink it? And if they smoke, how are they smoking? Or are they evaporating?” asked Blasco, who was not involved in the research.

“I would say, overall, we know there is a link between head and neck cancer now in cannabis, and we don’t know what the safe threshold is or if there is one,” he added. “And we don’t know if there’s a safe method to use it.”

The USC researchers say future studies exploring this link should include “more comprehensive data on cannabis use.”