Head and neck cancers (HNC) rank as the seventh most common cancers worldwide, affecting areas such as the oral cavity, pharynx, and larynx1 . While tobacco and alcohol remain the leading risk factors, recent research has raised concerns about the potential link between heavy cannabis use and increased risk of these cancers2 . Emerging large-scale studies suggest that individuals with cannabis use disorder (CUD), a condition characterized by problematic cannabis use, may face significantly higher risks of developing head and neck cancers compared to non-users3 4.
Cannabis Use and Head and Neck Cancer Risk
Head and neck cancers include malignancies of the mouth, throat, and voice box, with tobacco and alcohol as well-established risk factors that often act synergistically to increase cancer risk1 5. Cannabis smoke contains many of the same carcinogens found in tobacco smoke, such as polycyclic aromatic hydrocarbons and benzo[a]pyrene, which can cause DNA damage and inflammation in exposed tissues6 7. These harmful substances may contribute to cancer development through genotoxic (DNA-damaging) and epigenetic mechanisms8 .
“Our research shows that people who use cannabis, particularly those with a cannabis use disorder, are significantly more likely to develop head and neck cancers compared to those who do not use cannabis.”
— Niels Kokot, M.D., Keck School of Medicine, University of Southern California3
Epidemiological studies investigating the relationship between cannabis use and HNC risk have produced inconsistent and sometimes conflicting results, often complicated by confounding factors like tobacco and alcohol use, as well as limited data on cannabis exposure details such as frequency and duration9 1011. However, recent large cohort studies analyzing millions of medical records have provided more robust evidence.
One notable study analyzed data from over 116,000 individuals diagnosed with cannabis use disorder and nearly 4 million matched controls without cannabis-related diagnoses2 . This cohort had a mean age of 46.4 years and included 44.5% women2 . The study found that patients with cannabis use disorder had a significantly higher risk of developing any head and neck cancer compared to controls. Specifically, relative risks were elevated for:
| Cancer Subsite | Relative Risk Increase in Cannabis Use Disorder Cohort2 |
|---|---|
| Oral Cancer | More than 2 times higher |
| Oropharyngeal Cancer | Approximately 5 times higher |
| Laryngeal Cancer | More than 8 times higher |
| Sources: 2 | |
💡 Did You Know?
Cannabis use disorder triples the five-year risk of oral cancer, highlighting the need for screening and awareness among heavy cannabis users4 .
These associations remained consistent across different age groups and were independent of tobacco and alcohol use, suggesting a direct link between cannabis use disorder and HNC risk12 13. Another study focusing on oral cancer risk found that cannabis use disorder was associated with a more than threefold increased risk of oral cancer over five years, even after adjusting for smoking, age, sex, and body mass index14 4. Among smokers with cannabis use disorder, the risk of oral cancer was six times higher compared to smokers without cannabis use disorder4 .
Biologically, cannabis smoke increases the expression of epidermal growth factor receptor (EGFR), a protein often overexpressed in head and neck squamous cell carcinomas, which may promote tumor growth12 . Additionally, cannabinoids such as Δ9-tetrahydrocannabinol (THC) can suppress immune responses, potentially allowing tumors to evade immune surveillance, especially in tissues directly exposed to smoke4 . Preclinical studies have shown mixed results, with some suggesting anti-cancer effects of cannabinoids, but these findings have not been confirmed in human populations15 16.
Despite these findings, causality between cannabis use and head and neck cancer has not been definitively established, and further research is needed to clarify dose-response relationships and isolate the effects of cannabis from other lifestyle and socioeconomic factors2 1716. Lifestyle factors such as diet, oral hygiene, and socioeconomic status also influence HNC risk and complicate the assessment of cannabis-related risk5 .
Most providers do feel there is a real risk to develop head and neck cancer with most inhaled substances and exposures, whether they are tobacco or cannabis and others18 .
Implications for Cannabis Users
The growing evidence linking heavy cannabis use, particularly cannabis use disorder, to increased risk of head and neck cancers has important implications for users and healthcare providers. Cannabis is often perceived as a safer alternative to tobacco, but smoking cannabis still exposes users to harmful carcinogens and may increase cancer risk19 . Cannabis is typically smoked unfiltered and inhaled deeply, with smoke burning at higher temperatures than tobacco, potentially causing more intense inflammation and DNA damage in the upper aerodigestive tract13 .
For individuals diagnosed with cannabis use disorder, who often use cannabis daily and experience negative health or social effects, the risk of head and neck cancer appears notably elevated3 4. However, occasional or recreational cannabis use has not been clearly linked to increased HNC risk in current studies3 . It is important to note that cannabis use disorder is characterized by symptoms such as craving, tolerance, unsuccessful attempts to quit, and continued use despite problems3 .
Healthcare providers should discuss the potential risks of heavy cannabis use with patients, especially those with cannabis use disorder or other risk factors for head and neck cancer20 . Patients using cannabis for symptom relief related to cancer or its treatment should consult their care team before making changes based on emerging cancer risk data20 . Balanced communication is essential to avoid undue anxiety while ensuring informed decision-making20 .
“Just because you’re not smoking cigarettes doesn’t mean that what you are smoking is without risks.”
— Samantha Tam, M.D., Henry Ford Health19
Other risk factors for head and neck cancer remain critical to address, including tobacco smoking, alcohol consumption, and human papillomavirus (HPV) infection5 3. Smoking tobacco and drinking alcohol significantly increase HNC risk, and combined use more than doubles the risk5 19. HPV infection is linked to a growing proportion of oropharyngeal cancers, and vaccination is recommended to reduce this risk3 .
Signs and symptoms of head and neck cancer can include blocked sinuses, difficulty swallowing, pain in the neck or throat, sores or white patches in the mouth, and lumps near the jaw19 . Early detection improves treatment outcomes, so individuals with these symptoms should seek medical evaluation promptly.
- Be aware that heavy or problematic cannabis use may increase the risk of head and neck cancers.
- Avoid smoking cannabis, especially unfiltered and deeply inhaled forms, to reduce exposure to carcinogens.
- Discuss cannabis use openly with healthcare providers, particularly if using cannabis for medical reasons.
- Address other modifiable risk factors such as tobacco and alcohol use.
- Monitor for early signs of head and neck cancer and seek timely medical evaluation if symptoms arise.
