Moderate-certainty evidence shows cannabis-based medicines do not effectively relieve opioid-refractory cancer pain, and low-certainty evidence shows no benefit of CBD for advanced cancer pain.
Oncologists, palliative care physicians, cancer patients, and clinical guideline developers.
NNTB 16for patient global improvement with cannabis-based medicines — not clinically relevant (Cochrane review, moderate certainty)
What the researchers found
Meta-analysis of 14 studies (1,823 participants) found moderate-certainty evidence that nabiximols and THC are ineffective for opioid-refractory cancer pain, with an NNTB of 16 for patient global improvement — not clinically relevant.
Why it matters
Despite widespread belief that cannabis helps cancer pain, this Cochrane review provides the most comprehensive evidence to date that current cannabis-based medicines do not meaningfully add to existing cancer pain treatment.
The numbers in context
14 studies, 1,823 participants. Nabiximols/THC: NNTB 16 (95% CI 8-100) for PGIC improvement (moderate certainty). Pain intensity SMD -0.19 (not significant). CBD alone showed no added value. No herbal cannabis studies found.
How the study worked
Cochrane systematic review and meta-analysis of double-blind RCTs comparing cannabis-based medicines to placebo or active treatments for cancer pain in adults. GRADE assessment of certainty of evidence.
Who was studied
1,823 adults with cancer pain across 14 randomized controlled trials.
What this study cannot tell us
Only 14 studies met inclusion criteria. Most evidence is for nabiximols/THC; very limited evidence for CBD and nabilone. No studies of herbal cannabis. Short double-blind periods (2-5 weeks).
How to read the evidence
Cochrane systematic review with GRADE assessment provides the highest quality of evidence synthesis, with moderate certainty for main findings.
When this study was published
Comprehensive search through January 2023.
The bigger picture
This Cochrane review challenges the popular narrative that cannabis helps cancer pain. The finding that 10-15% of cancer patients have inadequate opioid pain relief underscores the ongoing need for new analgesic approaches, but current cannabis-based medicines do not fill this gap.
Replication
Cochrane systematic review; findings will be updated as new RCTs are published.
Funding
Not specified in abstract
Conflicts of interest
Not specified in abstract
Questions still open
- Would whole-plant cannabis or different formulations show different results?
- Are there specific cancer pain subtypes where cannabinoids might still be effective?
Read the original research
Cannabis-based medicines and medical cannabis for adults with cancer pain.
The Cochrane database of systematic reviews, 6(6), CD014915
Citation
Häuser, Winfried; Welsch, Patrick; Radbruch, Lukas; Fisher, Emma; Bell, Rae Frances; Moore, R Andrew. (2023). Cannabis-based medicines and medical cannabis for adults with cancer pain.. The Cochrane database of systematic reviews, 6(6), CD014915. https://doi.org/10.1002/14651858.CD014915.pub2