Cannabinoids for adult cancer-related pain: Systematic review and meta-analysis

Elaine G. Boland, Michael I. Bennett, Victoria Allgar, Jason W. Boland*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review


Objectives: There is increased interest in cannabinoids for cancer pain management and legislative changes are in progress in many countries. This study aims to determine the beneficial and adverse effects of cannabis/cannabinoids compared with placebo/other active agents for the treatment of cancer-related pain in adults. Methods: Systematic review and meta-analysis to identify randomised controlled trials of cannabinoids compared with placebo/other active agents for the treatment of cancer-related pain in adults to determine the effect on pain intensity (primary outcome) and adverse effects, including dropouts. Searches included Embase, MEDLINE, PsycINFO, Web of Science,, Cochrane and grey literature. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Results: We identified 2805 unique records, of which six randomised controlled trials were included in this systematic review (n=1460 participants). Five studies were included in the meta-analysis (1442 participants). All had a low risk of bias. There was no difference between cannabinoids and placebo for the difference in the change in average Numeric Rating Scale pain scores (mean difference -0.21 (-0.48 to 0.07, p=0.14)); this remained when only phase III studies were meta-analysed: mean difference -0.02 (-0.21 to 0.16, p=0.80). Cannabinoids had a higher risk of adverse events when compared with placebo, especially somnolence (OR 2.69 (1.54 to 4.71), p<0.001) and dizziness (OR 1.58 (0.99 to 2.51), p=0.05). No treatment-related deaths were reported. Dropouts and mortality rates were high. Conclusions: Studies with a low risk of bias showed that for adults with advanced cancer, the addition of cannabinoids to opioids did not reduce cancer pain. Trial registration number: CRD42018107662.

Original languageEnglish
Article numberbmjspcare-2019-002032
Pages (from-to)1-11
Number of pages11
JournalBMJ Supportive and Palliative Care
Early online date20 Jan 2020
Publication statusE-pub ahead of print - 20 Jan 2020

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  • cannabinoids
  • cannabis
  • neoplasia
  • other cancer
  • pain
  • systematic review

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