Prognostic impact of oral microbiome on survival of malignancies: a systematic review and meta-analysis

Background Recent studies have shown that there exists a significant correlation between oral microbiome and the occurrence of malignancies. However, the prognostic significance of oral microbiome for cancer patients remains unclear. The purpose of this meta-analysis is to evaluate the impact of oral microbiome on the survival of patients with malignant neoplasms. Methods We conducted a thorough literature search of PubMed, Embase, and Cochrane Library databases until September 2022. The hazard ratio (HR) with a corresponding 95% confidence interval (CI) was analyzed using Review Manager 5.4 software for survival outcomes, including overall survival (OS), disease-specific survival (DSS), progression-free survival (PFS), and disease-free survival (DFS). Results A total of 15 studies, covering 5191 samples with various types of cancers, were selected based on specified inclusion and exclusion criteria. In both univariate and multivariate analysis, patients with low diversity of the oral microbiome, or those with Fusobacterium-high/positive, or P. gingivalis positive in cancer tissue displayed poorer OS (univariate HR = 1.74; 95% CI 1.15-2.62; P = 0.009; multivariate HR = 1.56; 95% CI 1.07-2.27; P = 0.02), DSS (univariate HR = 2.06; 95% CI 1.50-2.84; P < 0.00001; multivariate HR = 1.80; 95% CI 1.48-2.20; P < 0.00001), and PFS/DFS (univariate HR = 2.00; 95% CI 1.12-3.58; P = 0.002; multivariate HR = 1.78; 95% CI 1.05-3.02; P = 0.003). Subgroup analysis revealed that Fusobacterium positive or high abundance in cancer tissues was associated with poor OS in multivariate analysis but had no statistical differences in PFS or DFS in univariate and multivariate analysis. Additionally, P. gingivalis positive in cancer tissue was also associated with worse OS. Conclusions Our meta-analysis suggests that the composition of the oral microbiome may play a significant role in predicting survival outcomes for cancer patients.