Adverse events associated with the use of cannabis-based products in people living with cancer: a systematic scoping review

To summarise the extent and type of evidence in relation to adverse events (AEs) associated with the use of cannabis-based products (CBP) in people living with cancer.

The Joanna Briggs Institute (JBI) methodology for scoping reviews was applied. A search was performed in MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCOhost), Scopus, Web of Science Core Collections and AMED (Ovid) from their inception to 7 May 2023. Primary studies reporting AEs associated with any form of natural or synthetic CBP use in any cancer care setting and location were included.

One hundred fifty-two studies were included, with the most prevalent being randomised controlled trials (RCTs) (n = 61), followed by non-randomised controlled trials (n = 26) and case reports (n = 23). CBP was mainly used in gastrointestinal, liver, or peritoneal cancer (n = 98) and haematological or lymphoid cancer (n = 92), primarily to manage nausea and vomiting (n = 78) and cancer pain (n = 37). The most common CBP ingredients were combinations of THC and CBD (n = 69), synthetic THC (n = 47), single compounds of THC (n = 42) and CBD (n = 16) with diverse forms, administration routes and doses. The primary methods of administration were oral (n = 94) and inhalation (n = 54). A broad range of AEs were reported; the most common were related to the nervous system (n = 118), psychiatric (n = 101) and gastrointestinal system (n = 81). Diverse patient characteristics, significant under-reporting and low-quality reporting were observed in many studies.

More rigorous research designs that prioritise comprehensive, standardised reporting of AEs and CBP use are required to fully elucidate the safety profile of CBP use in cancer care.