Microbiome Shifts in Bladder Cancer: A Narrative Review of Urobiome Composition, Progression, and Therapeutic Impact

Background/Objectives: Bladder cancer is a common malignancy with a high rate of recurrence and progression. Recent studies have identified that the urinary microbiome can be a key factor in tumor pathogenesis, progression, and outcomes. This narrative review is designed to summarize current evidence regarding the urobiome and explore its diagnostic and therapeutic potential. Methods: Studies between 2019 and 2024 were identified through the PubMed/MEDLINE and Google Scholar databases. Case reports and non-English-language articles were excluded. Results: The main findings revealed that specific bacteria, viruses, and taxa are linked to bladder cancer presence, progression, and response to immunotherapy treatment. Urinary microbiota differ by tumor type, sex, smoking status, and occupational exposure to toxins. Conclusions: Urinary microbiome and certain types of viruses present in urine may serve as promising tools to enhance bladder cancer diagnosis and predict treatment response. However, larger longitudinal studies are needed to confirm and establish these findings. Furthermore, integration of the urinary microbiome in clinical practice and public health strategies may reduce disease-related burden.