Are cannabinoids effective for treatment of pain in patients with active cancer?

Cannabinoids have been proposed for the treatment of patients with cancer pain, especially if standard treatment does not control symptoms. Using Epistemonikos database, which is maintained by searching 30 databases, we identified nine systematic reviews including seven trials that answer the question of interest, of which six are randomized trials. We performed a meta-analysis and generated a summary of findings table using the GRADE approach. We concluded it is unclear whether cannabinoids decrease pain and improve quality of life in patients with refractory cancer pain because the certainty of the evidence is very low, and it probably increases adverse effects substantially.