Cannabis is useful for cancer-related pain and nausea, and preclinical data suggest anti-tumor properties, but its immunomodulatory effects could potentially interfere with cancer immunotherapy and bone marrow transplants.
Oncologists, cancer patients using cannabis, and immunotherapy researchers.
Potential conflict between cannabis and cancer immunotherapy
What the researchers found
Current cancer applications of cannabinoids are mainly palliative (pain and anti-emetic effects). Preclinical data on anti-proliferative properties remain inconsistent, with no conclusive animal model or clinical trial data. Critically, the immunomodulatory effects of cannabinoids may conflict with cancer immunotherapy and bone marrow transplant approaches, where robust immune function is essential.
Why it matters
As immunotherapy becomes a standard cancer treatment, the potential for cannabis to dampen the immune response it relies on is a clinically important but understudied concern.
The numbers in context
No specific clinical outcome data. Review synthesized preclinical and clinical knowledge about cannabinoid immunomodulation in oncology.
How the study worked
Review covering preclinical models, limited clinical data, and the specific concern about interactions between cannabinoid immunomodulation and cancer immunotherapy.
What this study cannot tell us
Narrative review. Anti-tumor data are preclinical and inconsistent. Immunomodulatory interactions with immunotherapy are theoretical. No clinical trials address this interaction.
How to read the evidence
Thoughtful review raising an important clinical question, but based on indirect evidence and theoretical concerns.
When this study was published
2020 review.
The bigger picture
The potential contradiction between cannabis's anti-tumor properties and its immune-dampening effects highlights the complexity of using cannabinoids alongside modern cancer treatments.
Questions still open
- Should cancer patients on immunotherapy avoid cannabis? Could timed or targeted cannabinoid dosing avoid immune interference?
Common questions
Should cancer patients use cannabis during immunotherapy?
Can cannabis fight cancer directly?
Read the original research
The Highs and Lows of Cannabis in Cancer Treatment and Bone Marrow Transplantation.
Rambam Maimonides medical journal, 11(1)
Citation
Almogi-Hazan, Osnat; Khuja, Iman; Ritter, Sivan; Or, Reuven. (2020). The Highs and Lows of Cannabis in Cancer Treatment and Bone Marrow Transplantation.. Rambam Maimonides medical journal, 11(1). https://doi.org/10.5041/RMMJ.10391
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