Relationships between oral microbiome and head and neck squamous cell carcinoma: a systematic review

Abstract

Background: There is growing evidence about oral dysbiosis in patients with head and neck squamous cell carcinoma (HNSCC).

Methods: A Pubmed literature search was performed on March 2025, with "oral microbiome" and "head and neck cancer" keywords.

Results: Alterations in the oral microbiome have been described in patients with HNSCC, at the salivary and intratumoral level, with enrichment in bacteria associated with periodontal disease, and a relative reduction in commensal bacteria. A strong association between dysregulation of the oral microbiome and hallmarks of cancer has been demonstrated, including deregulation of cellular metabolism, sustained proliferative signaling, induction of hypoxia, immunosuppression, inflammation and genome instability.

Conclusions: The development of microbial models integrating salivary abundance of selected bacteria might favor non-invasive screening procedures in high-risk populations. Baseline oral microbiome appears as a significant prognosticator of both treatment efficacy and overall survival, highlighting new possibilities for modulation through medical intervention and treatment personalization.

Keywords: Head and neck cancer; Oral microbiome; Prognosis; Screening; Squamous cell carcinoma.