Multinational Association of Supportive Care in Cancer (MASCC) expert opinion/consensus guidance on the use of cannabinoids for gastrointestinal symptoms in patients with cancer.

Background: Gastrointestinal symptoms are common in patients with cancer, whether related to treatment or a direct effect of the disease itself. Patients may choose to access cannabinoids outside of their formal medical prescriptions to palliate such symptoms. However, clinical guidelines are lacking in relation to the use of such medicines for gastrointestinal symptoms in patients with cancer.

Methods: A systematic review of the evidence for the use of cannabinoids for symptom control in patients with cancer was undertaken. Search strategies were developed for Medline, Embase, PsychINFO, and the Cochrane Central Register of Controlled Trials, including all publications from 1975 up to 12 November 2021. Studies were included if they were randomized controlled trials of cannabinoids compared with placebo or active comparator in adult patients with cancer, regardless of type, stage, or treatment status. Articles for inclusion were agreed by all authors, and data extracted and summarized by two authors. Each study was scored according to the Jadad scale. This review was specifically for the purpose of developing guidelines for the use of cannabis for gastrointestinal symptoms, including chemotherapy-induced nausea and vomiting (CINV), chronic nausea, anorexia-cachexia syndrome, and taste disturbance.

Results: Thirty-six randomized controlled trials were identified that met the inclusion criteria for this review of gastrointestinal symptoms: 31 relating to CINV, one to radiotherapy-induced nausea and vomiting, and the remaining four to anorexia-cachexia and altered chemosensory disturbance. The populations for the randomized controlled trials were heterogeneous, and many studies were of poor quality, lacking clarity regarding method of randomization, blinding, and allocation concealment. For CINV, eleven RCTs showed improvement with cannabis compared to placebo, but out of 21 trials where cannabis was compared to other antiemetics for CINV, only 11 favoured cannabis.

Conclusion: Tetrahydrocannabinol (THC) and nabilone were more effective in preventing CINV when compared to placebo but are not more effective than other antiemetics. For refractory CINV, one study of THC:CBD demonstrated reduced nausea as an add-on treatment to guideline-consistent antiemetic therapy without olanzapine. The MASCC Guideline Committee found insufficient evidence to recommend cannabinoids for the management of CINV, nausea from advanced cancer, cancer-associated anorexia-cachexia, and taste disturbance. High-quality studies are needed to inform practice.