How Does Your Body’s Microbiota Affect Your Prostate Cancer Risk?

The human microbiota, which refers to the trillions of microorganisms residing in and on the human body, plays a crucial role in maintaining health and influencing various physiological processes. Emerging research has explored the potential links between the microbiota and prostate cancer, though the understanding of these relationships is still evolving. Importantly, we do not yet know whether any kind of supplement or effort to change the microbiota affects prostate cancer outcomes.

The gut microbiota, which influences overall immune function and systemic inflammation, may indirectly affect prostate health. Changes in the gut microbiota composition have been linked to various health conditions including some cancers, and could potentially impact prostate cancer risk.

Across multiple studies, significant differences in gut microbiota composition were observed between:

• Men who had positive and negative prostate biopsy results.
• Caucasian men who had prostate cancer and Caucasian men who had benign prostate hyperplasia.
• Japanese men who had high-grade prostate cancer and Japanese men who did not have prostate cancer or had a low-grade prostate cancer.
• Men with enlarged prostates and men without enlarged prostates.

However, this does not seem to be consistent across all races and regions. For example, a particular study showed differences of little to no significance in gut microbiome composition in Hispanic Caucasian men who had prostate cancer and without prostate cancer.

Testosterone

It is reported in a few studies that some intestinal bacteria can affect testosterone levels in humans. Conversely, testosterone can also change the gut microbiota composition. A study of young and elderly Japanese men reported a significant correlation between several bacteria in the gut microbiota and serum testosterone levels.

Inflammation

Chronic inflammation is believed to be a potential factor in the development and progression of prostate cancer. The gut microbiome can influence the inflammatory environment in the prostate, and specific microbial patterns may contribute to or mitigate inflammation.

Prostate microbiota

Multiple studies have observed that certain bacteria are more prevalent in the human prostate microbiota in men with prostate cancer than in men without prostate cancer. One such bacteria is Cutibacterium acnes (C. acnes), which has been found to colonize prostate tissue in rat models, resulting in chronic inflammation. Another genus of bacteria of interest is Escherichia. Colibactin, a metabolite produced by some strains of Escherichia, damages DNA and promotes carcinogenesis.

Another area of interest is the microbiota found in urine and prostatic fluid that comes into close proximity with the prostate gland. Several small-scale studies utilizing metagenomic analysis have indicated Streptococcus, another genus of bacteria, is more prevalent among individuals with prostate cancer. This suggests that the microbiota in urine and prostatic fluid may play a significant role in prostate cancer risk and development.

However, it's worth noting that urine and prostate tissue contain fewer bacteria than stool, and sequencing-based methods for detecting microbes in low-concentration samples are susceptible to contamination. To ensure reliable results, additional verification, including contamination-free sample collection methods and appropriate sequencing controls, is necessary.

Emerging evidence suggests that the composition of the gut microbiota may influence responses to cancer treatment, including immunotherapy for kidney cancer (although this treatment is generally ineffective for prostate cancer). Similarly, certain treatment methods may affect the composition of the gut microbiota. Understanding the interplay between the gut microbiota and treatment outcomes in prostate cancer is an active area of research.

Androgen deprivation therapy, which is a systemic treatment for prostate cancer, can influence the composition of the gut microbiota and in turn, the altered gut microbiota composition may influence response to immunotherapy. For example, Akkermansia muciniphila (A. muciniphila), a bacterium, is known to increase responses to immunotherapy. Androgen deprivation therapy increases the proportion of A. muciniphila. This suggests the potential of combining certain treatment methods to optimize their benefits. However, much more research is needed to confirm these relationships.

Relationships between the gut microbiota and other common prostate cancer treatments are also being studied. An in vivo study using a mouse model showed that castration decreased A. muciniphila while testosterone propionate supplementation increased A. muciniphila in the gut microbiota. As the gut microbiota in mice may differ from the human gut microbiota, more research needs to be done to access the role and considerations of bacteria such as A. muciniphila in prostate cancer treatment. In the future, the effects on the gut microbiota may become an important factor in determining treatment options.

It's important to note that the field of microbiome research is still relatively new, and many aspects of the interactions between the microbiome and prostate cancer remain to be fully understood. The influence of the microbiome on cancer development and progression is likely to be multifaceted and complex. As research continues, it may lead to new insights into preventive strategies, therapeutic interventions and personalized approaches to prostate cancer management.

If you have specific concerns about your prostate health or prostate cancer risk, it is recommended to consult with a healthcare professional for personalized guidance and advice based on the latest research and understanding.