Middle Ear Bacterial Colonization and Recurrence of Radiation‐Induced OME : A Prospective Study

ABSTRACT Objective To define the bacteriological characteristics of otitis media with effusion (OME) in nasopharyngeal carcinoma (NPC) patients following radiotherapy and determine whether bacterial colonization in the middle ear was associated with a higher risk of early recurrence of radiation‐induced OME (RI‐OME). Methods This prospective multicenter cohort enrolled patients with OME (with or without a history of radiotherapy for NPC) undergoing tympanocentesis. Middle ear effusion (MEE) samples were cultured and patients with RI‐OME were followed up for 24 weeks. Data on demographics, radiotherapy history, treatment, comorbidities, and effusion characteristics were collected. Recurrence patterns were characterized descriptively throughout the 24‐week post‐tympanocentesis follow‐up. Results A total of 93 RI‐OME patients and 115 non‐radiation‐induced (NRI)‐OME patients were included. RI‐OME patients had a 4.843‐fold higher risk of MEE bacterial culture positivity compared to NRI‐OME patients (OR = 4.843, p = 0.006). MEE cultures in RI‐OME patients showed higher proportions of opportunistic pathogens and drug‐resistant bacteria. Mucoid effusion was a significant risk factor for bacterial positivity in RI‐OME (OR = 8.553, p = 0.002). Male sex (OR = 12.120, p = 0.002) and bacterial colonization (OR = 10.239, p = 0.035) were associated with early recurrence (≤ 4 weeks post‐tympanocentesis) in RI‐OME patients; however, neither factor remained an independent predictor over the full 24‐week period. Conclusion RI‐OME patients demonstrated significantly higher MEE bacterial culture positivity rates than NRI‐OME patients. Although MEE bacterial colonization significantly impacted early recurrence, it lacked independent prognostic value for overall 24‐week recurrence. Thus, whether targeted antibacterial therapy can reduce recurrence rates warrants further investigation. Level of Evidence 3.