Cannabinoid use for appetite stimulation and weight gain in cancer care: Does recent evidence support an update of the European Society for Clinical Nutrition and Metabolism clinical guidelines?

Cannabinoids have been used medicinally for thousands of years. Clinical trials support their use for treatment of chemotherapy-induced nausea and vomiting and HIV- and AIDS-related anorexia. Cancer anorexia cachexia syndrome (CACS) is a common debilitating condition and is associated with poor prognosis. The 2016 European Society for Parenteral and Enteral Nutrition clinical guidelines on nutrition in cancer patients concluded that "there are insufficient consistent clinical data to recommend cannabinoids to improve taste disorders or anorexia in cancer patients." The increased attention that cannabinoids have received in recent years warrants an updated evaluation of the literature on this topic, as practitioners are likely to encounter cancer patients interested in cannabinoid use. A systematic literature search was performed to assess the current body of evidence concerning cannabinoid use for the stimulation of appetite and oral intake by cancer patients. Over the past 20 years, 6 randomized controlled trials have evaluated the impact of cannabinoids on appetite-related outcomes in oncology patients in comparison with a control group or placebo. Based on this literature, cannabinoids do not appear to improve appetite, oral intake, weight, chemosensory function, or appetite-related quality of life. Limitations of the literature include small sample sizes, lack of adjustment for confounding variables, and difficulties conducting true placebo-controlled trials with a drug that may result in psychoactive side effects. Further exploration of the impact of cannabinoid use on CACS by using large, well-designed clinical trials is needed.