Are cannabinoids with cancer immunotherapy contributing to early death? A call for caution and further study

Cannabis use in cancer care is increasingly common for symptom management, but emerging studies suggest potential interactions with immunotherapy that may reduce treatment efficacy. This review explores findings from recent studies, highlights the need for cautious interpretation and discusses the appropriateness of medicinal cannabis use during cancer immunotherapy. While three key studies (Taha et al., 2019; Bar-Sela et al., 2020; Hadid et al., 2024) observed lower response rates and reduced survival in patients using cannabis alongside immunotherapy, methodological concerns and demographic differences raise questions about their findings. Critiques by Piper et al. emphasise the need for larger, more rigorous trials with demographic controls-particularly regarding smoking status. Until stronger evidence is available, clinicians should weigh the benefits of symptom relief against potential treatment risks and ensure patients are fully informed about possible interactions.