Objectives To evaluate the safety and effectiveness of medical cannabis (MC) in reducing pain and concurrent medications in patients with cancer.
Methods This study analysed data collected from patients with cancer who were part of the Quebec Cannabis Registry. Brief Pain Inventory (BPI), revised Edmonton Symptom Assessment System (ESAS-r) questionnaires, total medication burden (TMB) and morphine equivalent daily dose (MEDD) recorded at 3-month, 6-month, 9-month and 12-month follow-ups were compared with baseline values. Adverse events were also documented at each follow-up visit.
Results This study included 358 patients with cancer. Thirteen out of 15 adverse events reported in 11 patients were not serious; 2 serious events (pneumonia and cardiovascular event) were considered unlikely related to MC. Statistically significant decreases were observed at 3-month, 6-month and 9-month follow-up for BPI worst pain (5.5±0.7 baseline, 3.6±0.7, 3.6±0.7, 3.6±0.8; p<0.01), average pain (4.1±0.6 baseline, 2.4±0.6, 2.3±0.6, 2.7±0.7; p<0.01), overall pain severity (3.7±0.5 baseline, 2.3±0.6, 2.3±0.6, 2.4±0.6; p<0.01) and pain interference (4.3±0.6 baseline, 2.4±0.6, 2.2±0.6, 2.4±0.7, p<0.01). ESAS-r pain scores decreased significantly at 3-month, 6-month and 9-month follow-up (3.7±0.6 baseline, 2.5±0.6, 2.2±0.6, 2.0±0.7, p<0.01). THC:CBD balanced strains were associated with better pain relief as compared with THC-dominant and CBD-dominant strains. Decreases in TMB were observed at all follow-ups. Decreases in MEDD were observed at the first three follow-ups.
Conclusions Real-world data from this large, prospective, multicentre registry indicate that MC is a safe and effective complementary treatment for pain relief in patients with cancer. Our findings should be confirmed through randomised placebo-controlled trials.
- supportive care
- symptoms and symptom management
Data availability statement
Data are available on reasonable request.
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Contributors SA: conceptualisation, data management, writing of original draft, review and editing. PK: formal analysis, manuscript review and editing. MV: data management, manuscript review and editing. YH: manuscript review and editing. MC-M: data management. AV: conceptualisation, manuscript review and editing, responsible for final version of the manuscript and guarantor.
Funding The QCR was supported by grants from the Canadian Consortium for the Investigation of Cannabinoids (CCIC), the Collège des Médecins du Québec (CMQ) and unrestricted grants from several licensed cannabis producers (Bedrocan, Mettrum and Tweed; these three companies merged during the study conduct into one company called Canopy Growth Corporation). Cedars Cancer Foundation and Rossy Cancer Network supported the Medical Cannabis Program in Oncology of the McGill University Health Center, which provided most data on oncology patients to the QCR.
Competing interests AV was a member of the Clinical Advisory Board for Tilray, Canopy Growth Corporation, Syqe and EmpowerPharm. Until March 2020, AV was the Research Director of Santé Cannabis, Montreal, Canada.
Provenance and peer review Not commissioned; externally peer reviewed.