Cannabis Use in Patients Seen in an Academic Radiation Oncology Department

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Cannabis use rates are increasing throughout the United States along with shifts in state-level policy. Patients with cancer use cannabis for a broad range of indications, but there is limited quality data to support many of these uses. To date, few studies have sought to understand cannabis use in populations of patients served by radiation oncology departments.Standardized electronic medical record prompts were used by clinicians for cannabis history documentation for 1050 adult patients seen for initial consultation or follow-up between 10/2020 and 2/2021 at an academic radiation oncology department. Cannabis use data, including recency/frequency of use, indication, and mode of administration, were later gathered using the Michigan Radiation Oncology Analytics Resource (M-ROAR) under an IRB-approved protocol. Cannabis use characteristics were summarized, and logistic regression was used to explore associations between age and gender and recent cannabis use.In total, 54 (5.1%) of 1050 unique patients declined to answer questions about cannabis use. Of the remaining 996 patients, 106 (10.6%) endorsed recent cannabis use (≤1 month ago), 71 (7.1%) noted remote use (> 1 month ago), and 819 (82.2%) denied history of cannabis use. The median age of those with recent cannabis use was 59.5 (IQR: 49.7-66.4) vs. 65.4 (IQR: 57.1-73.5) in all others. A multivariable logistic regression analysis revealed an association between age (OR 0.96; 95% CI: 0.95-0.97; P < 0.001) but not gender (male OR 1.24; 95% CI: 0.82-1.88; P = 0.310) and recent cannabis use. Patients noted pain (46.2%), anxiety (23.6%), insomnia (17.9%), "for the high" (17.0%), nausea (15.1%), poor appetite (14.2%), "to fight cancer" (4.7%), and depression (1.9%) as indications for use. The most common mode of administration was inhalation via smoking (47.2%), followed by oral (edibles, 36.8%), topical (15.1%), oral (drinks, 4.7%), vaping (3.8%), sublingual (1.0%), and rectal (1.0%). Most patients used cannabis daily (58.5%). Only 4 individuals (3.8%) noted use multiple times daily, while the remainder endorsed weekly (20.8%) or less than weekly (17.0%) use.Approximately 10% of patients seen in a radiation oncology department reported recent cannabis use for a variety of reasons. These findings suggest a need for: 1) collection of cannabis use history in radiation oncology departments, 2) efforts to destigmatize cannabis use to facilitate frank discussions between patients and providers, 3) patient education about the fact that cannabis is not an evidence-based cancer treatment, 4) recommendation against inhaled forms of cannabis, which may carry risk of pulmonary toxicity, and 5) careful application of proven therapies to address symptoms when appropriate to provide alternatives to cannabis. Further research is needed to assess changes in cannabis use patterns over the course of cancer treatment and to evaluate risks and benefits of cannabis use in patients with cancer.