Post-radiation middle ear effusion in NPC patients: Analysis of patient, tumour, and radiation factors

Objective: The purpose of this study was to investigate whether patient, tumour and radiation therapy factors are associated with development of middle ear effusion (MEE) in nasopharyngeal carcinoma (NPC) patients. Deign, Settings, and Participants: A retrospective review of NPC patients treated between January 2000 and June 2018 at Rabin Medical Center. Patient factors, tumour factors, radiation doses, and radiation fields were collected and outlined if needed (middle ear, eustachian tube [ET], tensor veli palatini [TVP], and levator palatini [LVP] muscles), then analysed and compared between patients with MEE and those without and between sides in patients with unilateral MEE. Main Outcome Measures and Results: Seventy-three patients were enrolled. Most were males (71.2%) with advanced-stage diseases (78%). At the time of diagnosis 14 patients (19.2%) presented with MEE. Following radiation, 18 patients, with no evidence of MEE at presentation, developed MEE. Tumour stage, histology, and laterality were not associated with development of MEE. Comparison of mean radiation field dosages including—gross target volume, clinical target volume, and patient target volume showed no association with post-radiation MEE. In addition, no difference was found in the radiation doses to the middle ear, ET or the LVP nor the TVP between ears with and without MEE. Conclusions: Post-irradiation MEE remains a common adverse effect in NPC patients. Surprisingly, tumour stage, tumour laterality, and histology were not associated with MEE. Similar findings were observed for total radiation doses and specific doses to the middle ear, ET, and ET muscles.