Frequent Cannabis Use May Elevate the Risk of Head and Neck Cancers

A recent study suggests that cannabis use might be associated with an increased risk of head and neck cancers. Published on August 8 in JAMA Otolaryngology-Head and Neck Surgery, the research indicates that individuals with cannabis use disorder are at a higher risk of developing cancers in the oral cavity, oropharynx, and larynx compared to those without the disorder.

Although comprehensive data on cannabis use in the U.S. is limited, the Centers for Disease Control and Prevention estimate that about 30% of cannabis users may have cannabis use disorder. This disorder is characterized by difficulty in controlling cannabis use, cravings, and unsuccessful attempts to quit, which can interfere with daily functioning.

The study’s findings suggest a potential link between cannabis use disorder and a heightened risk of head and neck cancers, which account for approximately 4% of all cancer cases in the U.S. However, the researchers caution that while an association has been observed, it is not yet clear to what extent cannabis use might directly increase the risk of these cancers.

As Dr. Niels Kokot, the study’s lead author and head and neck surgeon at Keck Medicine of USC, noted, “What this study indicates is that there is an association, but we don’t know yet how much.”

The research adds to our understanding of the possible connection between cannabis use and head and neck cancers, though further studies are needed to clarify these risks and their implications for cannabis users.

Impact of Cannabis Use on the Risk of Head and Neck Cancers

The study aimed to determine whether heavy cannabis use is linked to an increased risk of head and neck cancers, which can arise in areas such as the mouth, nose, sinuses, salivary glands, throat, and larynx.

“Previous studies attempted to establish a connection but were unable to do so due to various limitations,” explained Dr. Niels Kokot.

To overcome these limitations, Kokot’s team utilized data from TriNetX, a global database encompassing medical records of millions of individuals.

The researchers analyzed over four million records in the U.S., identifying 116,076 individuals diagnosed with cannabis use disorder. This group consisted of an approximately equal number of men and women, with an average age of 46.

Upon analyzing the data, the team discovered that individuals with cannabis use disorder had a significantly higher likelihood of developing head and neck cancers. The rate of oral cancer in this group was more than double that of the control group, the incidence of oropharyngeal cancers was nearly five times higher, and the occurrence of laryngeal cancers was over eight times greater.

This study challenges earlier research that suggested cannabis might lower the risk of certain cancers. However, as Dr. Luc Morris, a head and neck surgeon at Memorial Sloan Kettering Cancer Center, pointed out, most of those studies were conducted in lab settings, not on human subjects.

“The idea that cannabis could reduce cancer risk is largely based on preclinical research,” Morris noted. “There’s no solid evidence to suggest that cannabis decreases cancer risk.”

Some experts speculate that cannabis use could increase the risk of head and neck cancers in a manner similar to tobacco smoking, though this remains speculative. The precise mechanism by which cannabis might raise the risk of these cancers is still unclear.

Implications for Cannabis Users

While the research led by Dr. Niels Kokot highlights “some risk” associated with heavy cannabis use, it does come with limitations. One significant drawback is the lack of detailed participant information. Researchers only knew whether individuals had been diagnosed with cannabis use disorder, without insights into the duration or intensity of their cannabis use. This gap makes it difficult to pinpoint when cannabis use might begin to impact the risk of head and neck cancers, raising questions about the study’s relevance to the broader population.

Dr. Kokot emphasized the need for further research to identify the specific patterns of cannabis use that pose the greatest risk for head and neck cancers.

Moreover, it remains unclear whether cannabis itself directly increases the risk of these cancers. Dr. Luc Morris pointed out that individuals who use cannabis might also engage in other high-risk behaviors, such as smoking tobacco or heavy drinking, which are known to elevate cancer risk. The exact role of cannabis in cancer development is still not fully understood.

Lifestyle factors, including diet, exercise, and oral hygiene, along with social determinants like access to healthcare and income, also influence the risk of head and neck cancers.

Given the current uncertainty, Dr. Morris advises that not everyone should feel compelled to stop using cannabis, especially if it provides relief from chronic conditions. He cautioned against misinterpreting the study’s findings, stressing that there is no definitive evidence yet that cannabis promotes cancer growth.

If you’re concerned about your cannabis use, experts recommend consulting a healthcare professional to discuss how it might affect your overall health.

Fast Facts

• Heavy cannabis use may raise a person’s risk of head and neck cancer, according to a new study.

• The research found that people with cannabis use disorder were more likely to develop head and neck cancers compared to people who had not been diagnosed with the disorder.

• Experts stressed that the study suggests only a relationship between cannabis use and cancer and doesn’t prove causation.