Multicenter retrospective cohort study of the association of cannabis use with risk of head and neck cancer

Cannabis is the most commonly used illicit substance worldwide. Whether cannabis use in associated with head and neck cancer (HNC) is unclear. A multicenter cohort study used clinical records from a database that included 20 years of data from 64 US health care organizations. The cannabis-related disorder cohort consisted of 116,076 individuals, while the non-cannabis-related disorder cohort included 3,985,286 individuals. After propensity score matching for demographic characteristics, alcohol-related disorders, and tobacco use two groups of each 115,865 individuals were formed. People with cannabis use disorder had increased risk of any HNC (RR 3.49; 95% CI 2.78-4.39), oral cancer (2.51; 1.81-3.47), oropharyngeal cancer (4.90; 2.99-8.02), and laryngeal cancer (8.39; 4.72-14.90). The authors conclude that the study highlights an association between cannabis-related disorder and HNC risk.