Exploring the Diagnostic and Predictive Value of Oral Microbiome in Esophageal Cancer: A Systematic Review and Meta-Analysis.

The research interest in the oral microbiome's role in esophageal cancer is growing, yet a comprehensive synthesis of available evidence is still lacking. This study aimed to explore the effects of oral microbiome on the development of esophageal cancer through a systematic review of existing literature retrieved from the Embase, PubMed, and Web of Science databases. Eighteen studies published between 2015 and 2024 were obtained, involving 1191 cases and 1403 controls, mostly using oral saliva samples and 16S rRNA gene sequencing. Findings on alpha-diversity were inconsistent, while most studies reported significant beta-diversity differences between cases and controls. Notably, several investigations on esophageal squamous cell carcinoma showed higher levels of Prevotella, Porphyromonas, and Fusobacterium, while two studies on esophageal adenocarcinoma reported elevated levels of Actinomyces species. A fixed-effect meta-analysis of two studies showed that individuals with specific oral microbial signatures had significantly higher odds of developing esophageal squamous cell carcinoma (OR = 9.50; 95% CI: 5.89-15.29). Quality assessments highlighted methodological strengths but noted variability in group comparability and local applicability. These results reveal the potential of oral microbiome shift as an early detection biomarker and for developing personalized strategies in treating esophageal cancer, meriting further clinical investigation.