Objectives: Various jurisdictions have legalized cannabis for medical purposes. As with all psychoactive medications, medical cannabis carries a risk of diversion and accidental ingestion. These risks may be particularly high among long-term medical cannabis patients as safety practices may become less salient to patients once the treatment becomes part of everyday life. The current study examines whether patients who have used medical cannabis for longer periods differ from those who have used for shorter periods in terms of sociodemographic background and other key aspects of medical cannabis use. Furthermore, the study examines the relationship between length of medical cannabis treatment and risk factors related to storage and diversion. Finally, the study examines the extent to which oncologists provide information to their patients about safe storage and disposal.

Methods: One hundred twenty-one medical cannabis oncology patients were interviewed face-to-face and 55 oncologists participated in a survey about safe storage and disposal practices related to medical cannabis.

Results: Length of medical cannabis treatment was related to administration by smoking and using higher monthly dosages. In terms of risk for unsafe storage and diversion, length of medical cannabis was positively associated with using cannabis outside the home and having been asked to give away medical cannabis. Physicians did not report providing information to patients regarding safe storage and disposal practices in a regular manner.

Significance of results: Results suggest that there is an ongoing risk of unsafe storage and diversion over the course of medical cannabis treatment. Oncologists may need to give more consistent and continued training in safe storage and disposal practices, especially among long-term medical cannabis patients.

Keywords: diversion; legalization; medical cannabis; oncologists; oncology patients; storage; unintentional ingestion.