Bacteriological Identification, Characterization and Changes of Feces Microbiome in Prostate Cancer Patients Undergoing Radiotherapy.

Purpose: To investigate the bacteriological characteristics of the gut microbiome in patients with prostate cancer and changes during and after radiation therapy.

Patients and methods: Forty-one prostate cancer (PCa) patients treated with radiation therapy were included in the study. Fecal samples were collected at three points: before gold marker implantation into the prostate gland (K1), at the start (K2), and last day of radiotherapy (K3). Microbial identification was performed using MALDI-TOF MS, which allowed for precise identification at the species and genus levels. Blood biochemical parameters were assessed, and correlation analyses were performed.

Results: In total, 291 microbial isolates were identified, with the most common genera being Escherichia (N=120), Streptococcus (N=31), and Enterococcus (N=30). A significant decrease in E. coli was observed in K3 compared with K1 and K2, whereas Citrobacter appeared exclusively at K2. Additionally, liver enzyme levels decreased, and IL-6 levels increased during treatment. These findings indicate significant shifts in the gut microbiota due to radiotherapy.

Conclusion: Radiation therapy alters the gut microbiota composition in patients with PCa, reduces microbial diversity, and promotes the growth of opportunistic pathogens. These changes are linked to biochemical parameters, suggesting a potential impact on health. Further research is needed to explore microbiome-targeted interventions during treatment.