Cannabis use disorder was associated with at least a threefold increase in the risk for developing oral cancer over 5 years compared with those without cannabis use disorder, according to findings from a multicenter clinical cohort analysis published in Preventive Medicine Reports.
“Cannabis smoke contains many of the same carcinogenic compounds found in tobacco smoke, which have known damaging effects on the epithelial tissue that lines the mouth,” said study author Raphael Cuomo, PhD, Associate Professor in the Department of Anesthesiology at UC San Diego School of Medicine and a member of UC San Diego Moores Cancer Center. “These findings add to a growing body of evidence suggesting that chronic or problematic cannabis use may contribute to cancer risk in tissues exposed to combustion products.”
Study Methods and Rationale
With a growing availability and acceptance, both federally and socially, for cannabis use, many researchers believe it is important to understand its potential health risks. About 17.7 million people reported daily or near-daily cannabis use in 2022. Although not all can be considered cases of cannabis use disorder, especially as that requires a formal diagnosis, research suggests that up to 3 in 10 users have or will develop cannabis use disorder.
Dr. Cuomo set out to learn more about the relationship between cannabis use disorder and oral cancer. He conducted a retrospective cohort analysis of clinical records from the University of California Health Data Warehouse, including 45,129 eligible adults who were screened for drug use disorders between January 2012 and December 2019 without a prior oral cancer diagnosis. All were followed for 5 years to track oral cancer incidence rates.
Key Study Findings
A total of 949 patients (2.1%) developed cannabis use disorder, and 0.7% of those patients developed oral cancer compared with 0.2% in the non–cannabis use disorder group. The unadjusted odds ratio for developing oral cancer with cannabis use disorder was 3.24 (95% confidence interval [CI] = 1.50–7.00). After adjustments for smoking status and other factors were made, the odds ratio was 3.25 (95% CI = 1.47–7.17). In the case of tobacco smokers with cannabis use disorder, the odds ratio for developing oral cancer within 5 years was 6.2.
Dr. Cuomo also suggested that the immune-suppressing effects of tetrahydrocannabinol in cannabis could be contributing to the increased cancer risk. “These findings highlight the need to assess long-term oncologic risks of problematic cannabis use,” he concluded in his paper.
Disclosure: For full disclosures of the study authors, visit sciencedirect.com.
