Use of Cannabis and Odds Ratio for Oropharyngeal and Oral Cancer-A Cohort Study.

BACKGROUND: Widespread legalizations of cannabis in many states also cause increased interest in the adverse effects of its use, including increased risk for head and neck cancer.

METHODS AND RESULTS: To test the hypothesis that cannabis increases the risk for head and neck cancers, we have used the i2b2 platform and ICD 10 codes to access a large Hospital database and identify patients with head and neck cancer and patients who were cannabis users. Binary Logistic regression of factors such as demographics, smoking, alcohol consumption, and HPV vaccine history was used. The odds ratio for oropharyngeal cancer among cannabis users was 3.12. After logistic regressions, it remained significant after adjusting for gender, age, and race but became insignificant after adjusting for alcohol, cigarette smoking, and HPV vaccine (1.07, 0.87, 1.02), respectively. The odds ratio for oral cancer among cannabis users was 2.38 before adjustments. It remained significant after adjustment for gender, age, race, and HPV vaccine but became insignificant after adjustment for alcohol and cigarette smoking (0.7, 0.62). After adjusting for cannabis use, the odds ratio for oropharyngeal cancer in the alcohol users was 7.95 and 7.39 for smokers. The odds ratio for oral cancer after adjusting for cannabis in the alcohol users was 9.67 and 7.52 in the cigarette smokers. HPV vaccination had an inhibitory effect on both cancers.

CONCLUSIONS: Alcohol and cigarette smoking rather than the use of cannabis may play a major role in establishing an association between cannabis use and both types of head and neck cancers.