(Almost) Everything You Always Wanted to Know About Cannabis Science, but Were Afraid to Ask!

Abstract

Aim: It is estimated that approximately 25% of cancer patients are currently taking cannabis to alleviate symptoms of their disease and/or cope with the side effects of their treatment. Patients want to learn more about cannabis from their cancer healthcare team, but most Radiation Therapists (RTs) feel too uninformed to discuss this subject. The purpose of this abstract is to provide information about cannabis that is relevant and useful for RTs. Process: Cannabis is a broad term used to describe organic products derived from the Cannabis plant. The unique group of active chemical compounds found in cannabis are called cannabinoids. Among the more than 100 different types of cannabinoids, the most abundant and well-studied are delta9 tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the primary intoxicating compound of cannabis, which is responsible the euphoric “high”. CBD is a non-intoxicating constituent of cannabis. Terpenes are the third most prevalent compound in cannabis, these give cannabis its distinctive fragrance. Plants are selectively bred to produce particular THC/CBD ratios, and there are more than 200 medical strains currently available from licensed producers in Canada. Cannabis comes in many forms, including dried flower, processed oil, pharmaceutical grade pills and topical patches. Cannabis can be ingested by inhalation, orally, sublingually and topically. Each of these methods has its own rate of onset and duration of effects, and differences in the bioavailability of cannabinoids. Cannabinoids are absorbed into the blood, then rapidly distributed into the brain and other high perfusion tissues. They are then metabolized by CYP liver enzymes and eventually eliminated via feces or urine. All forms of cannabinoids work on the endocannabinoid system within the human body, which consists of a series of neuromodulators and their associated receptors located throughout the brain, peripheral nervous system and immune system. Benefits/Challenges: Cancer patients most frequently take cannabis to improve nausea and appetite, pain, stress and sleep, with 51% - 83% self-reporting a major benefit. The Canadian Cannabis Act (2018) provides access to cannabis for those over 18yrs via medical cannabis programs, prescription pharmaceuticals, pharmacies, provincial websites and retail storefronts. Despite widespread availability, there are multiple precautions and contraindications when considering taking cannabis. These include patient risk factors (e.g. schizophrenia, cardio-metabolic disorders, respiratory conditions), drug-on-drug interactions (e.g. anti-coagulants, statins, SSRIs), lifestyle risk factors (e.g. driving, working, travelling) and the development of a use disorder. Short term harms associated with cannabis use include impaired cognitive and motor function, tachycardia, anxiety and paranoia. Long term harms include impaired learning and memory and development of chronic bronchitis. Evidence-based guidelines are now available to lower the risks associated with taking cannabis. Impact/Outcomes Most RTs have little knowledge about the therapeutic use of cannabis by cancer patients, and <15% of patients receive any information about cannabis from their healthcare team. This leaves our patients exposed to cannabis myths and misrepresentations found during internet searches. Educational opportunities are urgently needed to provide RTs with information about the science of cannabis so they can support and advise their patients.