Igor Vainer

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1 INTRODUCTION Obstructive sleep apnea (OSA) is a prevalent condition characterized by repetitive episodes of partial or complete upper airway obstruction during sleep, leading to disrupted breathing patterns and oxygen desaturation (Veasey & Rosen, 2019). Beyond its immediate impact on sleep and oxygenation, OSA has been associated with a variety of comorbidities, including cardiovascular disease, diabetes and even chronic obstructive pulmonary disease (Huang et al., 2008).

This study investigated the association between patient, tumour, and radiation therapy factors including radiation doses to the middle ear, eustachian tube and its dilator muscles and the development of middle ear effusion (MEE) in nasopharyngeal carcinoma (NPC) patients. Seventy-three NPC patients with appropriate follow-up data were identified, most were males (71%) with advanced-stage diseases (78%). Post-radiation unilateral MEE was observed in 18 (25%) patients.