Influence of gut microbiome composition on treatment efficacy and toxicity in bladder cancer: A comprehensive meta-analysis.

768 Background: The gut microbiome has emerged as a critical factor influencing the efficacy and toxicity of cancer treatments. In bladder cancer, variations in microbiome composition may affect patient responses to therapy, including immunotherapy and chemotherapy. This meta-analysis aims to comprehensively evaluate the impact of gut microbiome composition on treatment outcomes in bladder cancer. Methods: The PubMed, Embase, Scopus and Cochrane databases were systematically searched from inception until June 2024 using relevant keywords. The pooled data were presented as Odds Ratio (OR) with 95% confidence intervals (CI) using Random Effects model in OpenMeta (version 5.3). The I 2 and X 2 statistics were used to evaluate inter-study heterogeneity. An I 2 value of >50% was considered significant heterogeneity. The subgroup analyses were conducted to identify specific microbiome profiles associated with different treatment responses. Results: A total of 20 studies comprising 2,500 bladder cancer patients were included in the meta-analysis. Patients with a higher abundance of beneficial bacteria such as Bifidobacterium and Lactobacillus had significantly better treatment responses (OR: 2.5, 95% CI: 1.8-3.4) and lower toxicity rates (OR: 0.6, 95% CI: 0.4-0.9). Conversely, an increased presence of pathogenic bacteria like Clostridium and Escherichia coli was associated with poorer outcomes (OR: 0.5, 95% CI: 0.3-0.8) and higher toxicity (OR: 1.9, 95% CI: 1.3-2.7). Conclusions: This meta-analysis highlights the significant influence of gut microbiome composition on the efficacy and toxicity of bladder cancer treatments. Identifying specific bacterial profiles associated with positive and negative outcomes could guide personalized treatment strategies and improve patient care. Further research is needed to understand the mechanisms underlying these associations and to develop microbiome-targeted therapies.