Is there a link between the microbiota (millions of bacteria) in your intestines and prostate cancer? It’s very likely, says a recent study published in Cancer Science.
A single purpose: explore the connection between prostate cancer and gut microbiota in a group of Japanese men. A single methodology: the profiles of the gut microbiota in men with and without high grade prostate cancer were compared. A single objective: determine whether the composition of the gut microbiota can be used as a new, non-invasive marker of high grade prostate cancer.
In search of a new marker...
The cancer is diagnosed via rectal examination and a number of clinical examinations that assess the severity of the cancer and the risk of progression, and help to determine the (sidenote:
Mohler JL, Antonarakis ES, Armstrong AJ, et al. Prostate Cancer, Version 2.2019, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2019;17(5):479-505.
). The vital screening and follow-up examination for prostate cancer is the prostate specific antigen (PSA) assay, although it does not accurately identify the grade of the cancer. The grade is assessed on a scale from 1 to 5, following examination of tissue samples from the prostate. At grade 1, patients’ prognosis is generally favourable, so it is recommended that no treatment be given, in order to avoid overtreatment which can often have an adverse impact. By contrast, patients with grade 2 prostate cancer and above require prompt, appropriate treatment. A new method for grading prostate cancers needs to be developed as a matter of priority to supplement the serum PSA test and avoid invasive examination.
...In the intestinal microbiota
In a previous study, the authors showed that in mice, obesity, a fatty diet and even certain molecules produced by the gut microbiota tend to promote the proliferation of prostate cancer cells. These results suggest that the gut microbiota could be used as a biomarker for determining how the cancer will progress. When they analysed the intestinal microbiota of patients who had undergone a prostate biopsy, the researchers found that three groups of bacteria were more abundant in patients with a high grade prostate cancer. To improve the accuracy of the diagnosis, the authors used a mathematical model and identified a further 18 types of bacteria to create the Fecal Microbiome Prostate Index, or FMPI. This FMPI index can be used to identify patients with a high grade prostate cancer with greater accuracy than conventional PSA assay.
While very encouraging, this study remains localised and the scope of the research is limited, with only men who were Japanese citizens being included. It now needs to be conducted in more patients, with different profiles, thereby confirming what are promising results.
