Influence of prior antibiotic treatment on survival in human cancer patients undergoing immunotherapy
I wrote a blog a little while back on the potential adverse effects of antibiotics other than the obvious concern over the induction of resistance.
The general drift of which is that we are only just starting to get the first inkling of an idea of the profound effects we induce when we prescribe antibiotics.
In the same vein, this just-published paper from human medicine should give pause for thought:
Association of Prior Antibiotic Treatment With Survival and Response to Immune Checkpoint Inhibitor Therapy in Patients With Cancer
David J. Pinato; Sarah Howlett; Diego Ottaviani, et al
JAMA Oncol. Published online September 12, 2019
This prospective study followed 196 patients receiving immune checkpoint inhibitor (ICI) therapy for a variety of tumours such as melanoma or certain lung cancers. ICIs enhance the immune response targeted against these tumours.
Overall survival in the 119 patients receiving treatment for non-small cell lung cancer was 2.5 months if the patient had received antibiotics in the month prior to starting ICI therapy and 26 months without prior antibiotic therapy. The same figures for melanoma were 3.9 vs 14 months and for other tumour types 5 weeks vs 11 months. It would be fair to call these results dramatic.
The usual caveats apply: this was not a large study and the authors do not claim to have a full understanding of how this apparent effect is mediated.
However, these effects were not trivial. Suspicion must be that, once again, the role of gut microbiota in regulating the immune system is in the frame.
This latest study backs up a previous analysis:
Oncologist. 2019 Jul
Cumulative Antibiotic Use Significantly Decreases Efficacy of Checkpoint Inhibitors in Patients with Advanced Cancer.
Tinsley N1, Zhou C2, Tan G3, Rack S3, Lorigan P1,3, Blackhall F1,3, Krebs M1,3, Carter L1,3, Thistlethwaite F1,3, Graham D4,3, Cook N4,3.
..whose authors reported very similar findings.
It seems that we should be thinking very carefully about which circumstances justify the need to prescribe antibiotics to cancer patients.