Fascinating headline: Cannabis abuse: A hidden cancer risk?

TOP LINE:

Cannabis-related illnesses are associated with a more than three-fold increased risk of head and neck cancer. The study analyzed data from over four million patients and highlighted the potentially carcinogenic effects of the substance.

METHODOLOGY:

• Researchers analyzed data from the global health research network TriNetX, which included more than 90 million men and women from 64 health organizations in the United States.
• More than 4.1 million patients were included in the analysis, including 116,076 people diagnosed with cannabis-related disorder and 3.9 million without the disorder. Cannabis-related disorders involve excessive use of cannabis with associated psychosocial symptoms, such as impaired social and/or occupational functioning.
• Patients with a cannabis-related disorder were matched with patients without this disorder based on demographic characteristics, alcohol-related disorders, and tobacco use.
• The primary outcome was the diagnosis of head and neck cancer, including subsites such as malignancies of the mouth, oropharynx, nasopharynx, larynx, hypopharynx and salivary glands.
• To compare the incidence of head and neck cancer between groups, propensity score matching and Poisson regression analysis were used.

TAKE AWAY:

• According to the researchers, patients with a cannabis-related disorder had a higher risk of head and neck cancer (relative risk (RR): 3.49; 95% CI: 2.78-4.39) than patients without this disorder.
• The risk of certain cancers was also higher in the group with cannabis-related diseases, including oral (RR 2.51; 95% CI 1.81–3.47) and oropharyngeal malignancies (RR 4.90; 95% CI 2.99–8.02).
• The RR for laryngeal cancer was significantly higher in patients with a cannabis-related disorder (RR: 8.39; 95% CI: 4.72–14.90).
• The results suggest that cannabis use disorders are associated with an increased risk of head and neck cancer and highlight the need for further research to understand the underlying mechanisms.

IN PRACTICE:

“In this cohort study, a diagnosis of cannabis use disorder was independently associated with a higher risk for later development of (head or neck cancer) and cancers of various sites of the head and neck in US adults. When restricting to cases of (such cancers) occurring more than one year after the diagnosis of cannabis use disorder, many of the associations were strengthened, demonstrating additional strength of the association,” the study authors wrote.

“The association between cannabis and head and neck cancer in this study spanned two decades during which use was increasing rapidly. If this association is causal, the burden of (head and neck cancer) from cannabis will continue to grow, perhaps dramatically,” said the authors of an editorial accompanying the journal article. “Given that cannabis is now a $20 billion industry in the United States alone, with availability, use and popularity increasing, this may be ‘déjà vu’ without adequate research to understand the potentially carcinogenic and health-promoting effects of cannabis. Or, in the words of Yogi Berra, ‘If you don’t know where you’re going, you might end up somewhere else.'”

SOURCE:

The study was led by Tyler J. Gallagher and Niels C. Kokot, MD, at the Keck School of Medicine at the University of Southern California in Los Angeles. It was published online August 8 in JAMA Otorhinolaryngology.

RESTRICTIONS:

The study included limited information on cohort composition and duration of follow-up, which may affect the generalizability of the results. The lack of direct information on duration, intensity and dosage of exposure limits the ability to analyze dose-response relationships. Potential inconsistencies in diagnosis and reliance on medical record codes may introduce bias. Cannabis use is likely underreported, which may reduce the relative risks found. The study was also limited by the lack of information on dosage and frequency of cannabis use, as well as some control factors, including alcohol and tobacco use.

DISCLOSURE:

Gallagher disclosed that he received grant funding from the Keck School of Medicine at the University of Southern California, Los Angeles. Additional details are provided in the original article.

Several editorial tools, including AI, were used to create this article. Human editors reviewed the content before publication.