Pain is a well-documented symptom of cancer, and pharmacological treatment options aside from opioids, which can have burdensome side effects, remain limited. Cannabinoids are compounds derived from the active components of the cannabis plant, and have been investigated for their potential medicinal use in treating cancer-related pain.

Aim To analyse the evidence regarding the use of cannabinoids to treat cancer-related pain.

Method A systematic search of databases was conducted to identify controlled trials that have tested cannabinoids to relieve cancer-related pain.

Findings Ten trials were included in this review: five randomised controlled trials, four crossover trials and one observational study. At least half of the trials had a low risk of bias. In six studies, the cannabinoids used in the intervention arms produced a statistically significant reduction in pain. However, only one study found that cannabinoids had a clinically significant effect. Side effects were consistent across studies, with the most common side effects being nausea, dizziness and somnolence. Pain relief and side effects were shown to be dose-dependent.

Conclusion The data does not provide sufficiently strong evidence to support the use of cannabinoids for treating cancer-related pain. The lack of evidence means that further research into the use of cannabinoids for treating cancer-related pain is required.