Discoveries continue to emerge regarding the relationship of our gastrointestinal (GI) microbiota to our overall health. Some new research in particular suggests that certain GI bacteria may influence the body’s response to certain drugs used to treat cancer. This interests us because GI microbiota appear to affect and be influenced by hormones, like testosterone. This thus has implications for prostate cancer treatments related to androgen suppression and androgen receptor blockade.
In a new study out of the US, researchers sought to find out more about changes in GI microbiota related to prostate cancer and its treatment. To do so, they examined the composition of GI microbiota in men both with and without prostate cancer. In addition, they looked at the relationship between GI microbiota and ADT therapies including both standard ADT drugs (like Lupron), and oral androgen receptor axis-targeted therapies (ATT; like enzalutamide).
This was a fairly small study involving 9 men without prostate cancer and 21 men with confirmed prostate cancer diagnoses. Five men were taking the standard ADT agents and nine were being treated with ATT.
The researchers found that men with prostate cancer had lower diversity of GI microbiota compared to those without prostate cancer. Moreover, this effect was found in all prostate cancer patients, irrespective of the medications they were on.
In addition, differences in GI microbiota composition were observed in men taking oral ATT versus the standard ADT depot injections. Of interest, the particular species of bacteria that was found to be more abundant in men taking oral ATT is thought to be involved in hormone biosynthesis. However, we need more research to clarify potential relationships between these GI bacterial species and circulating hormone levels. As the authors note, there is “an intriguing possibility” that GI microbiota composition may have implications to the men’s response to cancer treatments.
Larger studies are clearly needed to examine GI microbiota composition before, during and after ADT and ATT treatment, if we are to fully understand how the GI microbiome affects the efficacy of the different treatments. It may eventually be possible to modulate the GI microbiome to enhance treatment response and effectiveness.
To read the full article, see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6283851/
Reference:
Sfanos, K. S., Markowski, M. C., Peiffer, L. B., Ernst, S. E., White, J. R., Pienta, K. J., Antonarakis, E. S., & Ross, A. E. (2018). Compositional differences in gastrointestinal microbiota in prostate cancer patients treated with androgen axis-targeted therapies. Prostate cancer and prostatic diseases, 21(4), 539–548. https://doi.org/10.1038/s41391-018-0061-x