Genitourinary microbiomes and prostate cancer: a systematic review and meta-analysis of tumorigeneses and cancer characteristics.

Introduction: We assessed the association of genitourinary microbiomes with prostate cancer (PCa) tumorigeneses and cancer characteristics. Material and methods: A systematic search and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The primary endpoints were the association between relative abundance of genitourinary microbiomes and PCa compared to non-cancerous men/prostate specimen, high grade disease, and disease progression. The odds ratio (OR) was used as the summary statistic, and results were reported with 95% confidence intervals (CI). Results: Seventeen studies, comprising 2,195 patients were eligible for review and meta-analysis. The specific microbiomes in urine, prostate tissue, and prostate (or seminal) secretions were significantly more abundant in patients with PCa compared to men in the control groups in individual studies. Certain bacterial phyla, genuses, and species were significantly associated with PCa aggressiveness and disease progression in individual studies. The relative abundance meta-analysis of five urine microbiomes revealed no statistically significant differences between PCa patients and control groups (pooled OR, 1.35; 95% CI: 0.70-2.59). Conclusions: Our systematic review indicates that specific genitourinary microbiomes are more abundant in PCa and have a potential to predict/prognosticate disease aggressiveness and clinical outcomes. Nevertheless, these findings should be interpreted with caution owing to the significant heterogeneity among studies in terms of microbiome analysis method, assessed sample's characteristics, and individual biological behavior of microbiomes for analysis. Further studies are needed to validate these observations and shed more light on the role of the microbiome across the development and natural history of PCa.