Lower Rates of Hepatocellular Carcinoma Observed Among Cannabis Users: A Population-Based Study

Background: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and the fourth leading cause of cancer deaths in the world. The association between HCC and cannabis has been identified in mice; however, to our knowledge has not been identified in humans. Therefore, we aim to investigate the relation between HCC and cannabis use in humans. Methods: Using data from the National Inpatient Sample (NIS) database between 2002 and 2014, we identified the patients with HCC and cannabis use diagnosis using the International Classification of Disease 9(th) version codes (ICD-9). Then, we identified patients without cannabis use as the control group. We adjusted for multiple potential confounders and performed multivariable logistic regression analysis to determine the association between cannabis abuse and HCC. Results: A total of 101,231,036 patients were included in the study. Out of the total, 996,290 patients (1%) had the diagnosis of cannabis abuse versus 100,234,746 patients (99%) in the control group without cannabis abuse. We noticed that patients with cannabis abuse were younger (34 vs 48 years), had more males (61.7% vs 41.4%) and more African Americans (29.9% vs 14.2%) compared with the control group (P<0.001 for all). Besides, patients with cannabis use had more hepatitis B, hepatitis C, liver cirrhosis, and smoking, but had less obesity and gallstones, (P<0.001 for all). Using multivariable logistic regression, and after adjusting for potential confounders, patients with cannabis abuse were 55% less likely to have HCC (adjusted Odds Ratio {aOR}, 0.45, 95% Confidence Interval {CI}, 0.42-0.49, P<0.001) compared with patients without cannabis abuse. Conclusion: Based on our large database analysis, we found that cannabis use patients were 55% less likely to have HCC compared to patients without cannabis use. Further prospective studies are needed to assess the role of cannabis use on HCC.