Post-irradiation dysbiosis in patients with nasopharyngeal carcinoma having received radiotherapy - A pilot study.

OBJECTIVE: To compare the changes in the sinonasal mucosa microbiome in patients with nasopharyngeal carcinoma (NPC) before and after radiotherapy (RT), and to explore the pathogenesis of post-irradiation chronic rhinosinusitis (PI-CRS) and its association with dysbiosis. STUDY DESIGN: Prospective cohort study. SETTING: Unicenter, Tertiary referral hospital. METHODS: Included patients newly diagnosed with NPC. Samples of ostiomeatal complex mucosa were collected before and after RT. Microbiome analysis was conducted using 16S rRNA sequencing, and statistical analysis was performed. Subgroup analyses based on RT modality (proton therapy or photon therapy) RESULTS: Total of 18 patients were enrolled in the study, with 62.1% receiving intensity-modulated proton therapy (IMPT). Corynebacterium was the most dominant genus identified in both the pre- and post-RT groups, with a visible increase in Staphylococcus and a decrease in Fusobacterium genus in post-RT group. Alpha-diversity did not significantly differ between groups, although the beta-diversity analysis revealed a dispersed microbiota in the post-RT group. The functional prediction indicated a higher relative abundance of taxonomies associated with biofilm formation in the post-RT group. The subgroup analysis revealed the above changes to be more significant in patients who received photon therapy (Intensity modulated radiation therapy, IMRT). CONCLUSIONS: This is the first study to analyze the microbiome of patients with NPC after IMPT. We identified similarities between the post-RT microenvironment and that reported in patients with CRS, with a more apparent change noted in patients treated with IMRT. Further investigation is required to further elucidate the pathogenesis of PI-CRS and its relationship to post-RT dysbiosis, particularly IMPT.

Long-term late toxicities and quality of life for survivors of nasopharyngeal carcinoma treated with intensity-modulated radiotherapy versus non-intensity-modulated radiotherapy.

BACKGROUND: The purpose of this study was to investigate late toxicities and quality of life (QOL) of patients with nasopharyngeal carcinoma (NPC) with long-term survival after treatment by intensity-modulated radiotherapy (IMRT) versus non-IMRT. METHODS: An observational, cross-sectional study of QOL and late toxicities was conducted in 242 patients with NPC with survival of >5 years after treatment with IMRT (n = 100) or non-IMRT (n = 142) by using physician-assessed toxicities (Common Terminology Criteria for Adverse Events [CTCAE] version 4) and the patient-reported European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30-questions (EORTC QLQ-C30) and the Head and Neck 35-questions (EORTC QLQ-C30-H&N35) module. RESULTS: The IMRT group had both statistically (p < .05) and clinically (difference of predicted mean scores ≥10 points) better outcome in global QOL, cognitive functioning, social functioning, fatigue, and 11 scales of the head and neck module. Late toxicities, including neuropathy, hearing loss, dysphagia, xerostomia, and neck fibrosis were significantly less severe in the IMRT group. Multivariate analysis revealed that the radiotherapy (RT) technique was statistically significantly associated with late toxicities and QOL outcome after adjusting for other clinical and demographic variables. CONCLUSION: The use of the IMRT technique was associated with the improvement of physician-assessed late toxicities and patient-reported QOL in NPC survivors. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1026-E1032, 2016.