Cannabis use among cancer patients and survivors in the United States: a systematic review.

Background: How cannabis products are being used by cancer patients and survivors in the United States is poorly understood. This study reviewed observational data to understand the modes, patterns, reasons, discontinuation, and adverse experiences of cannabis use. Methods: PubMed and PsycINFO database searches were conducted between May 2022 and November 2022. Of the 1162 studies identified, 27 studies met the inclusion criteria. The intercoder agreement was strong (0.81). Results: The majority (74%) of the studies were cross-sectional in design. Study samples were approximately equal proportions of men and women and majority White participants. The prevalence of cannabis use based on national samples ranged between 4.8% and 22%. The most common modes of cannabis intake were topical application (80%), smoking (73%), vaping (12%), and ingestion of edible products (10%). Younger age, male gender, being a current or former smoker, and higher socioeconomic status were associated with greater likelihood of cannabis use. The main motive for cannabis use was management of symptoms due to cancer or cancer treatment such as pain, nausea, lack of sleep, and anxiety. A majority of the participants across studies reported that cannabis helped reduce these symptoms. Lack of symptom improvement, side effects such as fatigue and paranoia, cost, and social stigma were identified as some of the reasons for discontinuing cannabis use. Conclusions: It appears that cannabis may help cancer patients and survivors manage symptoms. However, more longitudinal studies are needed to determine whether positive experiences of cannabis use outweigh adverse experiences over time in this vulnerable population.