IMPACT OF ORAL MICROBIOME DYSBIOSIS ON THE RISK, PATHOGENESIS AND TREATMENT OF HEAD AND NECK CANCERS: A LITERATURE REVIEW

Abstract

Background: Head and neck squamous cell carcinoma (HNSCC) is the seventh most common malignancy worldwide and is associated with substantial morbidity and mortality. Although tobacco use, alcohol consumption, and human papillomavirus (HPV) infection remain the principal risk factors, growing evidence suggests that oral microbiome dysbiosis may contribute to tumor initiation, progression, and treatment response. Aim: This review summarizes current evidence linking oral microbiome dysbiosis with HNSCC, evaluates proposed biological mechanisms, and highlights major gaps requiring future investigation. Methods: A literature review was conducted by searching PubMed, Scopus, Web of Science, and Google Scholar for studies published through March 2026. Summary: Prospective cohort studies and case-control analyses have reported enrichment of periodontal-associated pathogens, including Fusobacterium nucleatum, Porphyromonas gingivalis, and Treponema denticola, in tumor tissues and saliva of patients with HNSCC, alongside depletion of commensal genera such as Streptococcus, Rothia, and Actinomyces. These organisms may influence carcinogenesis through NF-κB activation, Wnt/β-catenin signaling, epithelial–mesenchymal transition, apoptosis resistance, and immune modulation. Cancer therapies, particularly radiotherapy and chemotherapy, profoundly alter oral microbial communities and may worsen oral mucositis, candidiasis, and dental complications. Microbiome-targeted strategies, including probiotics, represent promising adjunctive approaches, although robust clinical validation is still required.