Changes of the Commensal Microbiome during Treatment are Associated with Clinical Response in Nasopharyngeal Carcinoma Patients

Abstracts The human microbiome has been suggested to be involved in the regulation of response to anticancer therapies. However, little is known regarding changes of commensal microbes in cancer patients during radiotherapy and whether these changes are associated with response to treatment. We conducted a prospective, longitudinal cohort with sixty-two newly diagnosed nasopharyngeal carcinoma (NPC) patients who were scheduled for radiotherapy-based treatment. Nasopharyngeal swabs were collected longitudinally before radiotherapy, during radiotherapy, and after radiotherapy. The nasopharyngeal microbiome was assessed using 16S rRNA amplicon sequencing. All patients were followed up to 24 months to define an early or late clinical response. We demonstrated the beta-diversity of the nasopharyngeal microbiome showed temporal changes throughout treatment. The magnitude of changes was stably and significantly different between the early and late responders. The temporal microbial networks among NPC patients with early response differed significantly from those with late response. Seven amplicon sequence variants (ASVs) mapped to Corynebacterium were lost during treatment. Twenty-eight abundant ASVs differed by patients’ responses throughout treatment. Among them, 10 ASVs differed between the early responders and late responders before getting any treatment and the difference was consistent along the radiotherapy course. This study addressed the temporal changes of the nasopharyngeal microbiome in NPC patients during radiotherapy and suggested a significant association with clinical response. The subject-specific changes of the nasopharyngeal microbiome might serve as a potential predictor for clinical response to radiotherapy. Importance The human microbiome has been suggested to be involved in the regulation of response to anticancer therapies. However, little is known regarding changes of commensal microbes in cancer patients during radiotherapy and whether these changes have an impact on response to treatment. In this longitudinal study of nasopharyngeal carcinoma patients, we demonstrate that the temporal changes of the nasopharyngeal microbiome in NPC patients during radiotherapy-based treatment and suggest a significant association with patients’ clinical response. We identify 28 abundant amplicon sequence variants differed significantly between the early and late responders throughout treatment. Among them, 10 are consistently differed by patients’ responses. These subject-specific changes might serve as a potential predictor for clinical response to radiotherapy. To the best of our knowledge, this is the first example that the commensal microbiome may influence the response to radiotherapy-based treatment in cancer patients.