Cannabis is one of the most commonly used substances in Canada, alongside alcohol and tobacco. In 2023, one in four adults and nearly half of youth aged 15 to 24 reported using it. Despite its widespread and increasing use following legalization in 2018, surprisingly little is known about the health effects of cannabis, including whether it affects cancer risk.
Unlike tobacco and alcohol, which have been studied extensively for decades, research on cannabis has lagged behind. Previous studies have been limited by small sample sizes, scarce lifestyle information and basic measures of cannabis use without capturing frequency, intensity or long-term use patterns.
Dr. Daniel Myran, an investigator at the Bruyère Health Research Institute and Research Chair at North York General Hospital, aims to change that. With $409,000 in funding from a Terry Fox New Investigator Award, he and his team are launching the most comprehensive study to date on cannabis and cancer risk in Canada, generating critical evidence to guide public health decisions.
Over the next three years, the team will link detailed health and lifestyle information from more than one million Canadians with national cancer records that capture every new diagnosis in the country. This will allow them to compare cancer risk across various levels of cannabis use, while accounting for other factors like smoking, alcohol use, diet and physical activity.
“This project will be the largest study on the association between cannabis use and cancer risk in the world,” says Dr. Myran. “Our goal is to provide the most reliable evidence to date to help guide cancer prevention, clinical advice and future research.”
The study will examine overall cancer risk as well as specific cancers that may be linked to cannabis use, including lung, head and neck, oral and testicular cancers.
By the end of the project, the hope is to clarify whether – and how – cannabis use is linked to cancer to help educate potential users, guide conversations between patients and physicians and inform future public health guidance.
As a family and public health physician, Dr. Myran focuses on preventing disease before it starts, and this award will help him build a long-term research program focused on understanding and reducing cancer risk factors.
“Receiving this award is a real privilege and honour personally, and a powerful vote of confidence in prevention-focused cancer research,” he says. “I want to thank donors for their generosity, which makes research like this possible and can turn evidence into real-world impact.”