A review synthesises evidence that the gut microbiome is a modifiable influence on cancer therapy, strongest for immune checkpoint inhibitors. Across melanoma, non-small-cell lung cancer and renal cell carcinoma, greater microbial diversity and immunostimulatory profiles are associated with better checkpoint-inhibitor response and survival.
Conversely, antibiotics and proton pump inhibitors are repeatedly linked to inferior checkpoint-inhibitor outcomes, probably by disrupting the microbiome. Microbiome-directed interventions, faecal transplant, diet, pre- and probiotics and live biotherapeutics, are in trials but remain investigational.
The usable message is defensive, not prescriptive: around the start of checkpoint-inhibitor therapy, avoid unnecessary antibiotics and review whether a proton pump inhibitor is genuinely needed, while not withholding an antibiotic a patient truly requires. There is not yet evidence to recommend any specific microbiome-modifying product.
- Higher gut microbial diversity is linked to better checkpoint-inhibitor response and survival.
- Antibiotics and proton pump inhibitors are associated with worse checkpoint-inhibitor outcomes.
- Avoid unnecessary antibiotics and review proton pump inhibitor need around immunotherapy.
- Do not withhold an antibiotic a patient genuinely needs.
- Microbiome-modifying products remain investigational, not recommended.
Why it matters
It reframes two everyday prescriptions, antibiotics and proton pump inhibitors, as potential modifiers of immunotherapy success.
Don't overread it
These are associations from a review; no microbiome intervention is proven to improve outcomes, and needed antibiotics should still be given.
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