Objective In the USA, the increase in state-sanctioned medical and recreational cannabis consumption means more young adults (YA) with cancer are using cannabis. Data and information are needed to characterise this use and frame much needed discussions about the role of cannabis in cancer care. To that end, this study’s objective was to describe consumption of cannabis in YA with cancer.

Methods Four hundred seventy-six patients with cancer ages 18–39 years at a large comprehensive cancer centre responded to a survey about their cannabis consumption. The survey was administered online between July 2019 and June 2020, and respondents were anonymous.

Results Fifty-two per cent (n=247) of respondents endorsed use within the last year; of these, half reported using cannabis prior to their diagnosis. Consumption was about equally distributed between smoking/inhalation and eating/drinking cannabis products. Seventy-five per cent of consumers used cannabis at least weekly. Top five primary reasons for use were pain, anxiety, nausea, sleep and recreation. More frequent consumption was associated with greater perceived improvement in certain symptoms. Cannabis products tended to be sourced from friends and family and information from non-medical sources. Most YA reported being comfortable discussing their consumption with providers.

Conclusions Many YA are using cannabis frequently to manage their cancer-related and treatment-related symptoms. Findings support the need for providers to consider cannabis use in treatment planning and symptom management with YA. Findings should help frame patient and provider discussions and herald much needed research on the effect of cannabis consumption on patient outcomes.