Patients with colorectal cancer and a history of cannabis use disorder had a more than 20 times higher risk of mortality within 5 years than those without cannabis use order, according to the results of a study published in Annals of Epidemiology.
The 5-year mortality rate in patients with a history of cannabis use disorder was 55.88% compared with 5.05% in patients without cannabis use disorder (odds ratio [OR] = 24.40; 95% CI = 11.39–52.34; P < .001).
“This study adds to a growing body of evidence suggesting that heavy cannabis use may have underrecognized impacts on the immune system, mental health and treatment behaviors—all of which could influence cancer outcomes,” stated lead study author Raphael Cuomo, PhD, Associate Professor in the Department of Anesthesiology at UC San Diego School of Medicine.
Study Methods and Results
The investigators sought to determine more of the long-term effects of cannabis, particularly whether or not cannabis use disorder affects survival outcomes in patients with cancer.
The study investigators examined data from 1,088 patients from the University of California Health Data Warehouse who had a diagnosis of primary colon cancer and a drug use disorder screening prior to the cancer diagnosis. Only 34 patients from the database had a history of cannabis use disorder.
Once adjusting the comparisons for key demographic and clinical factors, including CEA as a biomarker for disease severity, the risk was reduced to a 10-fold increase in risk of mortality (OR = 10.52; 95% CI = 5.76–19.22; P < .001).
The hazard ratio for risk of mortality over time in patients with a history of cannabis use disorder was 10.52 (95% CI = 5.76–19.22; P < .001), which reduced to 6.39 demographic and clinic factors included (95% CI = 2.85–14.31; P < .001).
“High cannabis use is often associated with depression, anxiety and other challenges that may compromise a patient’s ability to engage fully with cancer treatment,” said Dr. Cuomo, who is also a member of UC San Diego Moore’s Cancer Center. “However, this isn’t about vilifying cannabis. It’s about understanding the full range of its impacts, especially for people facing serious illnesses. We hope these findings encourage more research—and more nuanced conversations—about how cannabis interacts with cancer biology and care.”
Disclosure: For full disclosures of the study authors, visit sciencedirect.com.
