University of California San Diego School of Medicine researchers have linked higher colon cancer mortality with cannabis use disorder (CUD).
According to the researchers, CUD patients had a substantially higher five-year mortality rate (55.88 %) compared to patients without cannabis use disorder (5.05 %)
Based on the electronic health records of more than 1,000 colon cancer patients treated across the University of California Health system between 2012 and 2024, the evaluation delved into how cancer outcomes differed based on patients’ documented cannabis use before diagnosis, with various study controls in place.
The evaluation found patients diagnosed with cannabis use disorder prior to cancer diagnosis were 24.4 times more likely to die within five years of diagnosis compared to those without CUD.
While unsettling findings, lead author Raphael Cuomo, Ph.D. insists the study isn’t about vilifying cannabis, which is used by many cancer patients to ameliorate the effects of other treatment and the disease.
“It’s about understanding the full range of its impacts, especially for people facing serious illnesses,” said Dr. Cuomo. “We hope these findings encourage more research — and more nuanced conversations — about how cannabis interacts with cancer biology and care.”
Among the potential reasons for this link is CUD is frequently accompanied by depression, anxiety, and cognitive impairment. This can compromise adherence to cancer treatment, therefore negatively impacting treatment efficacy and increasing mortality risk.
“Socioeconomic disadvantage, stigma, and competing health concerns may further limit access to timely, high-quality oncologic care among patients with CUD,” says the study report. “Moreover, elevated healthcare utilization for non-cancer conditions may shift focus away from cancer management, contributing to poorer outcomes.”
The study has been published in the Annals of Epidemiology.
It’s important to note this link has been established among those with a history of cannabis issues. Other research has indicated cannabis might also have a role in colo-rectal cancer treatment. For example, this study from 2023 indicated the non-intoxicating cannabinoid CBD (cannabidiol), could inhibit invasion and metastasis in colorectal cancer cells.
In 2023, the USA Colo-Rectal Cancer Alliance said while not enough evidence existed to directly recommend medical marijuana as a treatment option, it supported the need for further research.
