Assessing the risk of gastrointestinal cancers among cannabis users compared to nicotine users.

10571 Background: Exposure to nicotine is a well-studied preventable cause of numerous malignancies, while the association of cannabis use with the development of cancer is not clear. Cannabis contains both carcinogens as well as compounds with antitumor activity, which inhibit chronic inflammation. The aim of this study is to assess the risk of gastrointestinal malignancy in cannabis users compared to nicotine users. Methods: A retrospective cohort study was conducted using TriNetX, a federated database of ~100 million patient records. Adult patients (≥18 years) were queried by ICD-10 coding to find variables of interest. Two groups were created: one group with a history of only cannabis use and the other with a history of only nicotine use. Then lifetime risk of nine different gastrointestinal cancers were assessed and compared between the two groups. 1:1 propensity score matching was conducted, adjusting for comorbidities and demographics, to calculate adjusted risk ratios (aRR) with 95% Confidence Interval for the comparative analysis. Results: A matched cohort of 413,628 patients revealed that cannabis only patients had a significantly lower lifetime risk of developing esophageal cancer (aRR[95%CI]): (0.456[0.364,0.572]), gastric cancer (0.492[0.41, 0.60]), pancreatic cancer (0.547[0.47,0.64]), liver & intrahepatic bile ducts cancer: (0.728[0.70,0.75]), colon cancer (0.351[0.32,0.38]), rectosigmoid cancer (0.699[0.59,0.83]), and rectal cancer (0.563[0.46,0.68]). No significant differences were seen for small intestinal cancer (1.21[0.88,1.6]) and anal cancer (0.87[0.67,1.14]). Conclusions: The results of this study suggest that the lifetime risk of developing numerous gastrointestinal malignancies is lower in cannabis users when compared to nicotine users. It is not clear if this relative risk reduction is due to the beneficial effects of cannabis or a lack of nicotine consumption and its associated effect on carcinogenesis. Long-term studies following cannabis users may provide a better understanding of the association of cannabis use with the risk of developing various malignancies. Additionally, the quantity of exposure to cannabis and its association with the risk of cancer should be further investigated. [Table: see text]