A population-based study of medical cannabis utilization in patients with cancer.

Abstract

124 Background: Between 2014 and 2018, access to cannabis for medical purposes was regulated by Health Canada. Surveys have demonstrated that cancer patients use cannabis to manage symptoms and side effects. Medical cannabis utilization patterns in cancer patients under Canada’s regulatory framework have not been well-described. We aimed to determine the proportion of cancer patients who used medical cannabis, timing of use in relation to cancer treatment and sociodemographic factors predicting use. Methods: The Alberta Cancer Registry was used to identify all patients age ≥ 18 diagnosed with invasive cancer in the province from April 01, 2014 to December 31, 2016. These cases were linked to records from the College of Physicians and Surgeons of Alberta database which collects data on patients who received an authorization for medical cannabis. Authorization was used as a surrogate for medical cannabis utilization. Univariate and multivariate logistic regression models were constructed to determine factors associated with medical cannabis utilization. Results: We identified 41,889 patients between April 1, 2014 and December 31, 2016. Median age at cancer diagnosis was 65 and 50% were female. Among these patients, 1,070 (2.5%) used medical cannabis. Of these patients, 541 (51%) used medical cannabis within 1 year of diagnosis, 248 (52%) within one year of the start of systemic therapy and 128 (41%) within one year of the start of radiation therapy. On multivariate analysis, patients aged 18-29 (OR 12.4, 95% CI 7.8-19.7) and those receiving systemic therapy (OR 2.0, 95% CI 1.7-2.4) were more likely to use medical cannabis (p < 0.001). There were 171 unique physicians who authorized medical cannabis of which only 3.5% (6/171) were oncologists. Conclusions: A small proportion of cancer patients used medical cannabis under Health Canada’s regulatory framework. Utilization was associated with a cancer diagnosis and receiving treatment. Younger patients and those undergoing systemic treatment were predictors of medical cannabis use. Further study is required to understand utilization patterns after cannabis legalization and how to incorporate these findings into patient-centered cancer care.