Study shows cannabis users 55% less likely to develop common liver cancer
Cannabis is already used as a medicinal treatment for cancer symptoms and cancer treatments, such as radiation therapy and chemotherapy. However, a recent study discovered that cannabis use may actually reduce the risk of developing hepatocellular carcinoma (HCC), one of the most common malignancies in the world.
The association between HCC and cannabis has already been identified in mice, but, to the researchers’ knowledge, not yet in humans, which prompted the investigation.
HCC represents the majority of primary liver cancers. The study notes that the World Health Organization expects the incidence of HCC to increase through 2030, with overestimates of more than one million liver cancer deaths. The United States saw a 43% increase in liver cancer death rates between 2000 and 2016.
Researchers at Georgetown University Hospital and Cleveland Clinic used data from the National Inpatient Sample (NIS) database between 2002 and 2014, identifying patients with HCC and diagnosis of cannabis use. The researchers then identified patients without cannabis use as a control group, adjusting for multiple potential confounders and performing multivariate logistic regression analysis to determine the potential association between cannabis use and HCC.
To the researchers’ knowledge, this was the largest study evaluating the relationship between cannabis use and HCC.
The study included a staggering total of 101,231,026 patients. In this group, 996,290 patients received the diagnosis of “cannabis abuse” against 100,234,746 in the control group without this diagnosis. Researchers also noted that cannabis-using patients were younger (34 vs. 48 on average), more male (61.7% vs. 41.4%), and more African American (29.9 % versus 14.2%), compared to the control group.
The authors also observed that cannabis users were more likely to engage in risky behaviors, including heavy drinking (28% versus 3%) and smoking (44% versus 9%). Viral hepatitis was also more prevalent among cannabis users, which the researchers said was linked to high-risk behaviors like intravenous drug use.
Although the study noted that patients using cannabis were 55% less likely to have HCC, compared to the control group, they indicated that this only confirmed the correlation. Essentially, the researchers were unable to confirm precise and direct causation.
In their discussion of the results, the researchers explain that CBD offers an explanation for their observations, “by providing protection against HCC or at least slowing the progression of the disease.” Moreover, the pharmaceutical development of compounds exerting the dual effect of CB1 antagonism and CB2 agonism may play a major role in the management of liver diseases.
The authors reveal that the NIS is an administrative database, intended for financial and administrative management rather than research. That said, they say the data could vary in the degree of detail and precision.
They also say that, among patients with a history of cannabis use, “we cannot determine if they are actively using cannabis or if they simply have a distant history of use.”
They also note the limitations of the cross-sectional study design, with potential recall bias in reporting exposures. This model also did not allow researchers to draw direct causal effects.
“Therefore, we suggest prospective clinical studies to better understand the mechanism by which various active ingredients, particularly CBD in cannabis, may possibly regulate the development of hepatocellular carcinoma,” they conclude.
Other recent studies demonstrated that cannabinoid therapies can stop the growth of liver cancer. Beyond the liver, studies have also shown the effectiveness of cannabis treatments in killing colon, pancreatic and breast cancer cells.
Will the future offer a range of preventative cannabis and CBD treatments for those most at risk of developing HCC and similar cancers? Of course, this early research only scratches the surface of the subject and the potential that cannabis has to offer, but it provides a solid foundation for future research and hopefully opens the door to more breakthroughs.