Cannabis may be beneficial in childhood cancer, but more evidence is needed

Cannabinoids may be beneficial for managing symptoms in children with cancer, a new review finds, but more extensive research is needed. 

A recent analysis of existing research suggests that while cannabinoids are increasingly being used to manage symptoms in childhood cancer, there is a lack of consistent evidence to determine the safety, and efficacy of these products.

Many children suffer from symptoms such as pain, anxiety, and weight loss related to cancer and its treatment, and over the last decade cannabis products—both synthetic cannabinoids and natural phytocannabinoids—have gained popularity with patients and families for managing such symptoms.

However, even in jurisdictions with legal access to medical cannabis, paediatric oncologists remain cautious to prescribe cannabis for their patients given the limited data to inform dosing, product selection, and safety monitoring.

A team of researchers at the Rady Faculty of Health Sciences at the University of Manitoba, carried out a review of medical literature to summarise existing knowledge about the potential benefits and harms of cannabis products in children with cancer.

The investigators identified 19 unique studies with a total of 1,927 participants with cancer: eight retrospective chart reviews, seven randomised controlled trials (RCTs), two open‐label studies, and two case reports. 

The products studied included medical-grade cannabinoids (such as the prescription drug nabilone), synthetic cannabinoids, and unspecified cannabis herbal extracts. Products were most commonly used to manage chemotherapy‐induced nausea and vomiting.

The researchers found that cannabinoids ‘may be beneficial’ for managing pain, nausea, and vomiting in children with cancer, especially in those who have not responded to standard treatments. 

Only a handful of the studies reported outcomes related to efficacy, but overall, cannabinoids were reported to be ‘superior’ in reducing nausea and vomiting in comparison with control groups. 

No serious cannabis-related adverse events were reported, however, in RCTs patients who used cannabinoids were more likely to experience drowsiness, feeling high, dizziness, and dry mouth. 

Trial participants who received cannabinoids were almost four times more likely to drop from the study due to adverse events, compared with the control group who received placebo.

A step towards more ‘rigorous studies’

Lead author, Dr Lauren Kelly, PhD, associate professor of pharmacology and therapeutics, and colleagues also noted that most studies did not adequately describe the types, dosing, frequencies, and routes of administration of cannabis products, and outcomes were mixed and were reported in different ways. 

They recommend that a set of standards should be developed for reporting cannabis exposures, cannabis‐related effects, and outcomes in this patient population.

The review concludes: “Cannabis products may have therapeutic applications for symptom management in children with cancer. However, there is a knowledge gap regarding the product compositions, doses, short- and long-term AEs [adverse events], and drug interactions. There is an urgent need to explore the real-world benefits and harms of cannabis in this vulnerable paediatric population.”

This review has informed the design of double-blind RCT, funded by the Canadian Cancer Society and Canadian Institutes of Health Research, which will look at the tolerability of cannabinoids in children with cancer across three Canadian children’s hospitals.

Dr Kelly commented: “It was difficult to measure benefit across studies, given a range of different outcomes and study designs; however, in interventional studies with active control groups, cannabinoids performed better in managing nausea and vomiting. Data are lacking on cannabinoids’ effects on pain, mood, sleep, and health-related quality of life.

“Given that some children report benefits and some children experience adverse events, it is critical that more rigorous studies evaluating the effects of cannabinoids on children with cancer are conducted and shared with parents, patients, and the health care community.”