Modulating the head & neck microbiome for cancer- prevention

The head and neck microbiome plays a critical role in maintaining epithelial homeostasis, regulating immune surveillance, and shaping inflammatory responses that influence carcinogenesis. Increasing evidence suggests that microbial dysbiosis within the oral and gut ecosystems contributes to the initiation and progression of head and neck cancers, particularly oral squamous cell carcinoma. Given that the microbiome is a modifiable risk factor, targeted modulation has emerged as a promising preventive and supportive strategy in HNC. This chapter highlights current knowledge on microbiome-based interventions, including dietary modification, probiotics, prebiotics, postbiotics, synbiotics, fecal microbiota transplantation, and lifestyle changes, with emphasis on their immunomodulatory and anti-inflammatory effects. These approaches aim to restore microbial balance, enhance barrier integrity, reduce chronic inflammation, and strengthen anticancer immune responses. The chapter also discusses mechanistic links between microbial metabolites and immune pathways, the relevance of the oral-gut axis, and emerging evidence connecting microbiome composition with treatment response and toxicity. Finally, key challenges such as inter-individual variability, site-specific microbial niches, safety considerations, and the need for longitudinal and mechanistic studies are addressed. Overall, microbiome modulation represents a promising, precision-oriented avenue for cancer prevention, risk reduction, and survivorship in head and neck oncology, although robust clinical validation is still required.