Prevalence of cannabis use among individuals with a history of cancer in the United States.

BACKGROUND Patients with cancer have played a key role in advocating for legal access to cannabis, but little is known about links between cancer and cannabis use or cannabis-related beliefs. The authors used data from a national survey to study these relationships. METHODS Nationally representative data collected by the National Survey on Drug Use and Health from 2015 to 2019 were acquired. Patterns of cannabis use and cancer history were examined and tested within age group subpopulations via domain analysis using survey weights. RESULTS Data for 214,505 adults, including 4741 individuals (3.8%) with past (>1 year ago) cancer diagnosis and 1518 individuals (1.2%) with recent (≤1 year ago) cancer diagnosis, were examined. Cannabis use was less common in those with past (8.9%; 95% CI, 8.0%-9.8%) or recent (9.9%; 95% CI, 6.9%-11.1%) cancer diagnosis than in those without a history of cancer (15.9%; 95% CI, 15.7%-16.1%). However, when analyses were stratified by age group, those 18 to 34 years of age were more likely to report past cannabis use, and those 35 to 49 years of age were more likely to report past or recent cannabis use if they had a history of cancer. Younger patients felt that cannabis was more accessible and less risky if they had a history of cancer. CONCLUSIONS Patients with cancer were less likely to report cannabis use, but there were different cannabis perceptions and use patterns by age. Age should be considered in studies of cannabis and cancer, and policy initiatives may be needed to aid provision of quality information on cannabis risk to those with cancer. LAY SUMMARY Cannabis (marijuana) use is increasing in the United States, but we do not have much information on the relationship between cannabis use and cancer. We studied information from a representative group of people and found that younger patients generally reported more past and/or recent cannabis use if they had been diagnosed with cancer whereas older individuals did not. Beliefs about cannabis risk and accessibility differed by age. Clinical trials to study cannabis should account for patient age, and accurate information about cannabis should be provided to help patients with cancer make decisions about cannabis use.