The effect of periodontal bacteria infection on incidence and prognosis of cancer: a systematic review and meta-analysis

Abstract Background Periodontal bacteria is the major pathogens in the oral cavity and the main cause of adult chronic periodontitis, but their association with incidence and prognosis in cancer is controversial. The aim of this study was to evaluate the effect of periodontal bacteria infection on incidence and prognosis of cancer.Methods A systematic literature search of PubMed, Embase, Web of Science and Cochrane Library databases was performed to obtain 39 studies comprising 7184 participants. The incidence of cancer was evaluated as odd ratios (OR) with a 95% confidence interval (95% CI) using Review Manager 5.2 software. Overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS), which were measured as hazard ratios (HR) with a 95% confidence interval (95% CI) using Review Manager 5.2 software.Results Our results indicated that periodontal bacteria infection increased the incidence of cancer (OR=1.25; 95%CI: 1.03–1.52) and was associated with poor OS (HR = 1.75; 95% CI: 1.40–2.20), DFS (HR=2.18; 95%CI: 1.24–3.84) and CSS (HR=1.85, 95%CI: 1.44–2.39). Subgroup analysis indicted that the risk of cancer was associated with Porphyromonas gingivalis (Pg) infection (OR=2.16; 95%CI: 1.34–3.47) and Prevotella intermedia (Pi) infection (OR=1.28; 95%CI: 1.01–1.63) but not Tannerella forsythia (Tf) (OR=1.06; 95%CI: 0.8–1.41), Treponema denticola (Td) (OR=1.30; 95%CI: 0.99–1.72), Aggregatibacter actinomycetemcomitans (Aa) (OR=1.00; 95%CI: 0.48–2.08) and Fusobacterium nucleatum (Fn) (OR=0.61; 95%CI: 0.32–1.16).Conclusion This meta-analysis revealed periodontal bacteria infection increased the incidence of cancer and predicted poor prognosis of cancer.