Cannabis Use in Oncology: A Study on Cancer Patients During Active Treatment at an NCI-Designated Cancer Center

A National Cancer Institute (NCI) funded study, conducted at the Sylvester Comprehensive Cancer Center at the University of Miami has shed light on cannabis use among adult cancer patients undergoing active cancer treatment.

The research, involving 385 patients, sought to understand cannabis use patterns, sources, and reasons for use among cancer patients undergoing treatments i.e. as chemotherapy, radiation, surgery, and immunotherapy. The study found that 41% of participants reported using cannabis during treatment. Among those used cannabis during treatment, most were younger, US-born individuals, and those with disabilities.

This suggests cannabis is particularly popular among patients with specific sociodemographic backgrounds who might seek alternatives for symptom management. The cancer stage appeared to play a significant role in cannabis use.

Patients in advanced cancer stages, especially those in Stage 4, reported the highest prevalence of cannabis use, with 60% consuming it to manage their symptoms. Patients diagnosed with Stage 2 cancer showed the lowest cannabis use during treatment. This trend indicates that as cancer progresses, particularly in advanced or palliative care stages, patients increasingly turn to cannabis, likely for symptom relief that traditional treatments may not fully address.

The study also found variations in cannabis use depending on the type of treatment patients were undergoing. Patients undergoing radiation reported the highest rates of cannabis use (53.3%), followed by chemotherapy (43.8%), and around 36.4% of those receiving immunotherapy or surgery. Most patients cited mood improvement, pain relief, and nausea reduction as primary reasons for use.

These motivations align closely with the well-known side effects of cancer therapies, reinforcing the idea that patients are using cannabis to manage treatment-related symptoms that conventional medications may not entirely alleviate. Cannabis was obtained primarily from dispensaries/medical cannabis stores and local dealers, with most patients starting use before their diagnosis.

Notably, these patients showed a preference for Cannabidiol (CBD) and Delta-8 tetra-hydro cannabinol (THC), which are less psychoactive than the more common Delta-9 THC. About 35% used CBD-dominant products, and 18.3% reported usage of Delta-8 THC products likely chosen for their symptom relief potential without the more intense psychoactive effects associated with Delta-9 THC.

Patients also reported varied methods of consumption, with smoking joints as the most common (61.5%) and store-bought edibles, especially candies, preferred among those choosing edible options. Despite its usage prevalence, many patients did not disclose their cannabis use to their healthcare teams.

Only 54% of those using cannabis informed their cancer doctors and just 39% received a recommendation from a healthcare provider. The reasons behind this gap in communication could range from concerns about stigma and healthcare provider support to worries about potential drug interactions.

However, the study notes that over 70% of patients using cannabis felt comfortable discussing their usage with healthcare providers, hinting at a willingness to engage in open discussions if they felt supported. The study emphasizes the need for open patient-provider communication about cannabis use to address potential risks, such as drug interactions with chemotherapy, immunotherapy, and other cancer treatments.

Principal Investigator and Senior Author, Dr. Denise C Vidot (Left) and Lead Author, Dr. Amrit Baral (Right)

As healthcare providers learn more about the complex interplay between cannabis and cancer therapies, open dialogue could help optimize treatment and mitigate adverse effects. In summary, this study highlights cannabis’s growing role in oncology and its potential as an adjunctive therapy, particularly in palliative care, offering insight that could lead to more evidence-based recommendations in the future. The authors recommend further research to better understand the effects of cannabis on cancer treatment outcomes and to explore how best to integrate it into supportive cancer care.

Cannabis Use Among Cancer Patients During Active Treatment: Findings From a Study at an NCI-Designated Cancer Center

Authors: Amrit Baral, Bria-Necole A. Diggs, Ranya Marrakchi El Fellah, Connor McCarley, Frank Penedo, Claudia Martinez, Denise C. Vidot

Denise C. Vidot: Principal Investigator and Senior Author