Assessing Benefits and Harms of Cannabis and Cannabinoid Use Among a Cohort of Cancer Patients Treated in Community Oncology Clinics

SUMMARY Cancer patients suffer from a multitude of debilitating symptoms associated with cancer and cancer treatment, many of which are not relieved with prescription medications. In hopes of managing these symptoms, many patients are turning to cannabis, with recent estimates of cannabis use among cancer patients ranging from 24-40%, primarily for physical and neuropsychiatric symptom relief, despite limited evidence of benefits and uncertain risks. This is, in part, due to increased availability of cannabis as more states legalize use. The expanding cannabis market, with varying regulations, limited product standards and few marketing restrictions, has resulted in a marketplace filled with diverse product types (e.g., smoked cannabis, vapes, edibles, topicals) with unpredictable cannabinoid concentrations, often exceeding that of therapeutic benefit (THC>15%). These products are associated with acute intoxicating effects and long-term adverse effects. Furthermore, THC and CBD, the primary cannabinoids, may be hepatotoxic, affect the metabolism of chemotherapy, and result in drug interactions that could enhance chemotoxicity. Furthermore, cannabis’ immunosuppressive effects could dampen immune responses and alter the efficacy of immune checkpoint inhibitors. Despite this, patients generally report that cannabis improves cancer-related symptoms. Current evidence for clinical benefits of cannabis is mixed and often inconclusive, largely due to small sample sizes and/or cross-sectional data. To better understand the benefits and risks of cannabis and cannabinoid use during cancer treatment, rigorous longitudinal studies of patient cohorts that document details of cannabis use (i.e. product type, frequency, cannabinoid ratios and potency, and patterns of use) are needed. We aim to achieve this goal by collaborating with the National Cancer Institute Community Oncology Research Program (NCORP), a national network of community oncology clinics. We will recruit a sample of 2000 newly diagnosed cancer patients with breast cancer, non-small cell lung cancer, colorectal cancer, melanoma, or non-Hodgkin lymphoma, to assess the benefits and risks of cannabis and cannabinoid use during treatment. Participants will complete monthly online surveys for 12 months to assess cancer-related symptoms and severity, as well as detailed cannabis and cannabinoid use. This will allow us to (1) describe the longitudinal patterns of use among adult cancer patients during treatment and the effect of individual, clinical and community-level factors on these patterns, and (2) determine the potential benefits and harms of use on cancer and treatment-related symptoms (e.g., nausea/ vomiting, anxiety, neuropathy). We will also assess potential pharmacokinetic and pharmacodynamic effects of use with cancer treatment and changes in inflammatory and toxicity markers by collecting and analyzing biospecimens in a subgroup of lung cancer patients. These data will provide a better understanding of the temporal relationship between heterogeneous patterns of cannabis and cannabinoid use and cancer symptom management; information that will contribute significantly to the design of future clinical trials in cancer care.