null Medical cannabis a valuable option for cancer pain relief

A new study conducted at the RI-MUHC suggests that, as a complementary therapy for cancer patients, medical cannabis could be used safely and effectively to reduce pain and opioid use.

Montreal - Medical cannabis could be a safe complementary treatment for pain in cancer patients, according to a new observational study conducted at the Research Institute of the McGill University Health Centre (RI MUHC). It could also help reduce the total number of medications and opioids taken by patients, suggests the study published online in BMJ Supportive & Palliative Care.

Antonio Vigano, MD, M.Sc., is a scientist in the Cancer Research Program and conducts research in the Centre for Outcomes Research and Evaluation at the Research Institute of the MUHC
Antonio Vigano, MD, M.Sc., is a scientist in the Cancer Research Program and conducts research in the Centre for Outcomes Research and Evaluation at the Research Institute of the MUHC

“We have demonstrated that regulated medical cannabis products can be incorporated into the care of cancer patients safely and effectively,” says Dr. Antonio Vigano, senior author of the study, a scientist in the Cancer Research Program at the RI-MUHC and the director of the Cancer Rehabilitation Program and the Medical Cannabis Oncology Program at the Cedars Cancer Centre of the MUHC. “After three months, the patients we followed showed clinical and statistically significant reductions in pain scores, which were maintained over one year. They were also able to reduce their pain medication over time.”

The study also found that products with a balance between the active ingredients tetrahydrocannabinol (THC) and cannabidiol (CBD), rather than a dominance of one or the other, seem to be more effective.

The results of the study are based on data from the Quebec Cannabis Registry (QCR), which compiles a wide range of data from several institutions and clinics across Quebec, collected directly from 3,000 patients who were initiated on cannabis for medical purposes between May 2015 and October 2018. The QCR was created in 2015 at the RI-MUHC by Dr. Mark Ware and since 2019, has been led by Dr. Vigano. A recent paper by Dr. Ware and Dr. Vigano on the QCR has shown that medical cannabis directed by physicians appeared to be safe and effective within three months of initiation for a variety of medical indications.

Pain affects a majority of patients undergoing cancer treatment

According to the authors of the study, 55 per cent of patients undergoing anticancer treatment and 66 per cent of patients with advanced, metastatic or terminal disease experience pain. A variety of medications, including opioids, are usually prescribed for pain relief. However, one third of patients still experience pain.

With the aim of finding out if medical cannabis could be used safely and effectively to manage cancer-related pain and reduce pain medication, the researchers included 358 adults with cancer in their study. The patients’ average age was 57; nearly half (48 per cent) were men; and the most common cancer diagnoses were genitourinary (60 patients), breast (59 patients), followed by bowel, lung and blood cancer (43 patients respectively).

The researchers analyzed pain intensity, symptoms, total number of medications taken and daily morphine use at three-month intervals (i.e., at the time of the first medical cannabis prescription, and then three, six, nine and twelve months later). Overall pain severity and pain relief, as well as pain interference with daily life in the previous 24 hours, were also assessed.

Conclusive results

Statistically significant decreases were observed at three, six and nine months for worst and average pain intensity, overall pain severity, and pain interference.

The researchers identified 15 adverse events that occurred in 11 patients: 13 were non-serious and two were serious, but did not appear to be related to medical cannabis.

The two most common side effects were sleepiness, reported by three patients, and fatigue, reported by two. Only five patients stopped taking medicinal cannabis because of side effects.

The study authors stress that randomized, placebo-controlled trials should be conducted to confirm the results of their study and that research should continue to tailor treatments to each individual.

“Medical cannabis is a medication that needs some theoretical knowledge and clinical experience in order to achieve best clinical results. More research is needed to define more effective and standardized ways to personalize medical cannabis treatments, as some patients may respond better, while others may be more prone to side effects,” says Dr. Vigano, who is also a specialist in palliative care, an associate professor at McGill University and the co-leader of the Biomedical Axis of the McGill Research Centre for Cannabis.

About the study

The study Medical cannabis is effective for cancer-related pain: Quebec Cannabis Registry results was conducted by Saro Aprikian, Popi Kasvis, MariaLuisa Vigano, Yasmina Hachem, Michelle Canac-Marquis and Antonio Vigano.


About the RI-MUHC

The Research Institute of the McGill University Health Centre (RI-MUHC) is a world-renowned biomedical and healthcare research centre. The institute, which is affiliated with the Faculty of Medicine of McGill University, is the research arm of the McGill University Health Centre (MUHC) – an academic health centre located in Montreal, Canada, that has a mandate to focus on complex care within its community. The RI-MUHC supports over 450 researchers and around 1,200 research trainees devoted to a broad spectrum of fundamental, clinical and health outcomes research at the Glen and the Montreal General Hospital sites of the MUHC. Its research facilities offer a dynamic multidisciplinary environment that fosters collaboration and leverages discovery aimed at improving the health of individual patients across their lifespan. The RI-MUHC is supported in part by the Fonds de recherche du Québec – Santé (FRQS).

Media contact

Fabienne Landry
Communications coordinator, Research
McGill University Health Centre
(514) 812-7722

May 4, 2023