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On May 5, 2023, we reported on a study published in BMJ Supportive & Palliative Care that examined the safety and effectiveness of medical cannabis in reducing pain and concurrent medications in patients with cancer.
Researchers tapped data on participants in the large, prospective, multicenter Quebec Cannabis Registry (QCR). QCR data were gathered for 358 adults with cancer for 3.5 years (May 2015–October 2018). Participants were referred by general practitioners or specialists and enrolled by physicians across the province of Quebec who agreed to prescribe medicinal cannabis within the QCR research framework.
Specific products authorized for participant treatment were THC-dominant (24.5%), THC:CBD-balanced (38%), and CBD-dominant (16.5%); oral administration was the route most frequently recommended (59%).
Outcomes associated with medicinal cannabis use were measured using the Brief Pain Inventory),Revised Edmonton Symptom Assessment System, the Medication Quantification Scale (MQS), and morphine equivalent daily dose (MEDD).
Pain intensity was rated, using validated measures, on a 0 to 10 scale with 0 reflecting no pain and 10 indicating the worst possible pain. Pain relief was measured from none (0%) to complete (100%). Two summary measures assessed overall pain severity and pain interference over the preceding 24 hours.
Medicinal cannabis seemed to be safe and well tolerated, with only 15 moderate to severe side effects reported by 11 patients, 13 of which were regarded as minor. The 2 most common side effects were somnolence, reported by 3 patients, and fatigue, reported by 2. Two serious side effects (pneumonia and a cardiovascular event) were deemed unlikely to have been linked to medicinal cannabis. Only 5 patients stopped taking medicinal cannabis because of side effects. Statistically significant decreases were observed at 3, 6 and 9 months for worst and average pain intensity, overall pain severity, and pain interference [with daily life] (P<.01 for all).
Overall, THC:CBD balanced products were associated with better pain relief than either THC-dominant or CBD-dominant products.
Note from authors
"Real-world data from this large, prospective, multicentre registry indicate that MC [medical cannabis] is a safe and effective complementary treatment for pain relief in patients with cancer. Our findings should be confirmed through randomised placebo-controlled trials."