Nasopharyngeal carcinoma and microbiome: Evidence and implications.

Nasopharyngeal carcinoma (NPC) is raising concern in its endemic regions due to its high propensity for metastasis and frequent late-stage diagnosis. The growing recognition of the microbiome's role in cancer has sparked interest in studying its association with NPC. The microbial composition of the nasopharynx, oral cavity, and gut has been correlated with NPC risk, with the intra-tumoral microbiome potentially shaping the tumour microenvironment, influencing tumour progression and therapeutic responses. Given these associations, non-invasive, radiation-free screening tools utilising oral and nasopharyngeal bacteria have been developed. Although patients typically respond well to radiotherapy, many suffer from treatment-related complications such as oral mucositis. Consequently, several studies have been conducted to investigate strategies targeting the microbiome to alleviate these complications and improve patient outcomes. This review integrates cross-site microbial evidence, identifying underexplored opportunities in NPC microbiome research, while underscoring the need for standardised approaches to realise their clinical potential.