The use of cannabinoids in palliating cancer-related symptoms: a narrative review

Despite uncertain efficacy, cannabinoids and derived products are becoming increasingly used in the field of palliative care for oncologic patients. Cannabinoids chiefly include psychoactive tetrahydrocannabinol (THC) and nonpsychoactive cannabidiol (CBD). Use of and research interest in THC, CBD, and combination THC/CBD products have increased in recent years, particularly after the Agriculture Improvement Act of 2018 made cannabis plants with <0.3% THC no longer controlled substances, and many states recently legalized THC use altogether. To provide an updated review of this topic, we reviewed randomized controlled trials with >50 patients studying cannabinoid use in cancer patients. We found that THC products, including THC and THC/CBD combination products, are helpful for treating chemotherapy-induced nausea/vomiting. CBD products were not helpful for this indication. For most other studied indications (anorexia/cachexia, mood, general global symptoms), there was no convincing evidence to support widespread cannabinoid use in cancer symptom management. The evidence for treating cancer-related pain with THC/CBD products is somewhat conflicting. We conclude that, apart from using THC products to treat chemotherapy-induced nausea/vomiting, cannabinoid products should not be routinely recommended for cancer supportive care. Further research in the form of large randomized controlled trials is warranted in this area.