Prognostic indicators and microbial landscape of post-radiation nasopharyngeal necrosis in nasopharyngeal carcinoma patients

BACKGROUND: Post-radiation nasopharyngeal necrosis (PRNN) is a serious complication in patients with nasopharyngeal carcinoma (NPC) treated with radiotherapy, and is often accompanied by infections such as sinusitis, otitis media, or central nervous system infections. This study retrospectively examined the clinical features, microbial profiles, treatment approaches, and prognostic factors of patients with PRNN to improve clinical management. METHODS: Patients with NPC diagnosed with PRNN at Taipei Veterans General Hospital between September 2005 and April 2021 were reviewed. The data included demographics, cancer staging, treatment history, complications, and PRNN management. Microbial cultures from necrotic tissues were analyzed. Patients were categorized as cured or uncured based on post-treatment mucosal healing. Statistical analysis identified predictors of uncured or persistent PRNN. RESULTS: During the study period, 872 patients with nasopharyngeal carcinoma were treated, of whom 30 (24 males and 6 females; mean age, 60.6 years) developed PRNN, with an incidence of 3.4%. Fourteen (46.7%) patients underwent re-irradiation, and 14 (46.7%) had local recurrence. Sinusitis occurred in 19 patients (63.3%), otitis media in 13 (43.4%), and central nervous system infections in 4 (13.3%). Microbiological cultures were available for 26 patients. Polymicrobial infections were identified in 17 patients (65.4%), predominantly involving aerobic bacteria (80.8%), most commonly Staphylococcus spp. (53.8%), followed by Klebsiella spp. and Pseudomonas aeruginosa (26.9% each). Fungi and anaerobic bacteria were detected in 9 patients (34.6%). Sixteen patients (53.3%) underwent surgical debridement, and 11 (36.7%) required endovascular treatment for carotid blowout syndrome (CBS). Complete mucosal healing was achieved in 10 (33.3 %) patients. CBS and re-irradiation significantly predicted refractory PRNN (adjusted odds ratio 9.6, p = 0.034). CONCLUSION: Patients with NPC and PRNN present with diverse pathogens and management challenges. Re-irradiation and CBS are key predictors of poor outcomes, underscoring the need for vigilant care in high-risk patients.