Medical Cannabis Authorization in Patients with Cancer in the Pre-legalization Era: A Population-based Study.

BACKGROUND: Studies show that cancer patients use cannabis to manage symptoms and side effects. Medical cannabis is regulated by Health Canada; authorization patterns amongst cancer patients have not been well-described. We aimed to describe medical cannabis authorization in Alberta, Canada.

METHODS: The Alberta Cancer Registry was used to identify all patients age ≥ 18 diagnosed with invasive cancer from April 01, 2014 to December 31, 2016. These cases were linked to records from the College of Physicians and Surgeons of Alberta. Univariate and multivariate logistic regression models were constructed to determine factors associated with medical cannabis authorization.

RESULTS: We identified 41,889 patients with cancer between April 1, 2014 and December 31, 2016. Of these patients 1,070 (2.6%) had a medical cannabis authorization. Fifty one percent (541/1,070) were authorized to use medical cannabis within 1 year of diagnosis, 52% (248/549) within one year of the start of systemic therapy and 41% (128/312) within one year of the start of radiation therapy. Patients aged 18-29 (OR 12.4, 95% CI 7.8-19.8), patients living in the Calgary zone (OR =1.8, 95% CI 1.6-2.1), those with advanced disease (stage III/IV OR= 1.2, 95% CI 1.0-1.4) and those receiving systemic therapy (OR 2.0, 95% CI 1.7-2.4) were more likely to have an authorization for medical cannabis (p < 0.001).

CONCLUSIONS: A small proportion of cancer patients were authorized to use medical cannabis between 2014 and 2016 in Alberta. Authorization was associated with a cancer diagnosis and receiving treatment. Younger patients, those with advanced stage disease and those undergoing systemic treatment were predictors of medical cannabis authorization.