A comparative study of oral and gut microbiota for differentiating benign pulmonary nodules from lung cancer.

Objective: The differentiation between benign pulmonary nodules and early-stage lung cancer remains a significant clinical challenge due to the lack of highly specific non-invasive biomarkers. While the gut-lung axis has emerged as a critical player in pulmonary diseases, the concurrent evolution of oral and gut microbiota across the spectrum from benign nodules to lung cancer remains poorly characterized. This study aimed to investigate the compositional and dynamic changes in oral and gut microbiota across different stages of lung carcinogenesis, with particular emphasis on distinguishing tumor-specific alterations from nodule-related changes by incorporating benign nodules as a critical control group. Methods: In this retrospective case-control study, we enrolled 111 participants, including healthy controls (C, Results: Lung cancer was associated with significant remodeling of both oral and gut microbiota. While salivary α-diversity remained stable between groups, gut microbial richness (Chao1 index) was significantly increased in lung cancer patients compared to non-tumor individuals ( Conclusion: Lung cancer progression is accompanied by stage-specific remodeling of the oral-gut microecology. The incorporation of benign nodule controls enables the identification of tumor-specific microbial alterations with high diagnostic efficacy. Salivary