Researchers have found a significant difference in the gut microbiota of patients with prostate cancer compared with those who have benign biopsies. Although the finding is an association, it could partly explain the relationship between lifestyle effects and geographic differences in prostate cancer. The study was presented at the European Association of Urology Annual Congress (EAU22).

Gut microbiota are the collection of microbes in the gastrointestinal tract, and they affect processes and mechanisms in the body. The state of gut microbiota has been linked to many conditions, even in organs that are far from the intestines, but their role in prostate cancer is not understood.

Peter Boström, MD, PhD, and colleagues at the University of Turku used samples collected from patients enrolled in a prospective multicenter clinical study (Multi-IMPROD; ClinicalTrials.gov identifier: NCT02241122). They sequenced the gut microbiota of 181 patients who were suspected to have prostate cancer and who were undergoing prostate cancer diagnostics. The microbiota samples were collected at the time of their prostate biopsies after magnetic resonance imaging scans.

Sixty percent of the patients were diagnosed with prostate cancer, and their gut microbiota profiles were significantly different from those who had benign biopsies. The patients diagnosed with cancer had increased levels of Prevotella 9, members of the family Erysipelotrichaceae, and Escherichia-Shigella, a pathogen that causes diarrhea. They also had lower levels of Jonquetella, Moryella, Anaeroglobus, Corynebacterium, and CAG-352 than patients who were not diagnosed with cancer.

Dr. Boström said, “There are significant variations in prostate cancer rates around the world, which could be due to genetic factors or differences in health-care policies, but also variance in lifestyle and diet. The difference in gut microbiota between [patients] with and without prostate cancer could underpin some of these variations. More research is needed to look at the potential for using gut microbiota for both diagnostic and preventive strategies.”

Prostate cancer is the most common male cancer globally, but varying rates in different parts of the world are little understood. It is common in most Western countries and less common elsewhere. Though it is known to be hereditary, there is evidence that individuals who emigrate from low- to high-incidence areas have an increased risk of prostate cancer in their lifetimes, and their offspring have the risk of the high-incidence region.

Lars Dyrskjøt Andersen, MSc, PhD, Professor of Molecular Medicine at Aarhus University and member of the EAU22 Scientific Congress Committee of Urology, commented, “This is a striking finding from a large, well-conducted trial. We should be careful with observed associations when it comes to complicated epidemiology, and no cause-and-effect measures can be determined based on this, but certainly the gut microbiota could be an important area to investigate further to enhance our understanding of prostate cancer risk.”