Cannabis Did Not Appear to Weaken Immune Markers Relevant to Cancer Immunotherapy
A systematic review of 40 clinical studies found no meaningful changes in immune parameters with cannabis use, suggesting cannabis may not interfere with immune checkpoint inhibitor cancer therapy.
Quick Facts
What This Study Found
Analysis of 40 clinical studies (including 9 RCTs) found no change in cytokines, T-cell counts, or CRP in most studies with cannabis exposure. Among autoimmune disease patients, cannabis improved clinical symptoms while objective immune markers remained unchanged. Immune markers relevant to checkpoint inhibitor function did not appear associated with cannabis use.
Key Numbers
40 studies included, 9 RCTs. No change in cytokines, T-cell counts, or CRP in most studies. Clinical symptom improvement in autoimmune patients despite unchanged immune markers. No evidence of altered immune parameters relevant to ICI function.
How They Did This
Systematic review searching Ovid Medline for clinical studies investigating cannabis use in humans and the immune system. Preclinical studies and case reports were excluded. Forty studies met criteria, including 9 randomized placebo-controlled trials.
Why This Research Matters
Many cancer patients use cannabis for symptom management while receiving immunotherapy. Preclinical data suggesting cannabis causes immunosuppression has raised concerns, but this clinical review found no evidence that translates to meaningful immune changes in humans.
The Bigger Picture
The gap between preclinical immunosuppression findings and clinical null results suggests that cannabis effects on immunity may be more nuanced in humans than lab studies indicate. This is reassuring for the growing number of cancer patients using both cannabis and immunotherapy.
What This Study Doesn't Tell Us
Most included studies were not specifically designed to assess cannabis-immunotherapy interactions. Heterogeneous cannabis exposure definitions. Few studies focused on cancer patients receiving ICIs specifically.
Questions This Raises
- ?Would prospective studies in ICI-treated patients confirm these findings?
- ?Do specific cannabinoids (THC vs CBD) differ in their immune effects?
- ?Could cannabis even enhance immunotherapy through anti-inflammatory pathways?
Trust & Context
- Key Stat:
- No meaningful immune changes with cannabis across 40 clinical studies
- Evidence Grade:
- Moderate: systematic review of 40 studies including 9 RCTs, but most studies were not designed to test cannabis-immunotherapy interactions specifically
- Study Age:
- Published in 2025
- Original Title:
- The impact of cannabis on immune checkpoint inhibitor therapy: a systematic review of immunomodulatory effects of cannabis in patients with and without cancer.
- Published In:
- Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 33(3), 166 (2025)
- Database ID:
- RTHC-06034
Evidence Hierarchy
Analyzes all available research on a topic using a structured method.
What do these levels mean? →Frequently Asked Questions
Can cancer patients use cannabis during immunotherapy?
This systematic review found no evidence that cannabis meaningfully alters immune parameters relevant to checkpoint inhibitor function. While this provides some reassurance, the authors recommend additional well-controlled prospective studies in this specific population.
Does cannabis suppress the immune system?
Preclinical studies suggest cannabis can cause immunosuppression, but this review of 40 human clinical studies found no meaningful changes in immune markers including cytokines, T-cell counts, and CRP. The disconnect between lab and clinical findings suggests human immune effects may be more nuanced.
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Cite This Study
https://rethinkthc.com/research/RTHC-06034APA
Behling-Hess, Caroline; Simonson, Grant; Salz, Talya; Fleege, Nicole; Zylla, Dylan. (2025). The impact of cannabis on immune checkpoint inhibitor therapy: a systematic review of immunomodulatory effects of cannabis in patients with and without cancer.. Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 33(3), 166. https://doi.org/10.1007/s00520-025-09218-x
MLA
Behling-Hess, Caroline, et al. "The impact of cannabis on immune checkpoint inhibitor therapy: a systematic review of immunomodulatory effects of cannabis in patients with and without cancer.." Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer, 2025. https://doi.org/10.1007/s00520-025-09218-x
RethinkTHC
RethinkTHC Research Database. "The impact of cannabis on immune checkpoint inhibitor therap..." RTHC-06034. Retrieved from https://rethinkthc.com/research/behling-hess-2025-the-impact-of-cannabis
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.