Middle ear effusions after radiotherapy: Correlation with pre-radiotherapynasopharyngeal tumor patterns

Objective: The purpose of this study was to assess whether pretreatment tum or patterns of nasopharyngeal carcinoma (NPC) can predict the status of the middle ear after radiation treatment. Materials and Methods: Pretreatment and follow-up magnetic resonance imagin g (MRI) was performed in 32 patients (64 ears) who had radiation therapy fo r NPC. For the purpose of analysis, the ears were placed into their pre-rad iation therapy tumor pattern groups and the presence of middle ear effusion (MEE) with regard to eustachian tube (ET) invasion or;displacement was ide ntified. Results: MEEs were present in 31 (48.4%) ears after radiation therapy. All of the MEEs that resolved were in the preradiation therapy groups where tum or invasion of the eustachian tube was present irrespective of the amount o f ET displacement. There was, however, no significant difference for resolv ed MEEs between ears with ET invasion or displacement (p = 0.32 and p = 0.7 1,respectively, Fisher's exact test). The MEEs occurred with significantly greater frequency in ears with minor ET displacement than in those with maj or ET displacement (p = 0.013, Fisher's exact test) as well as in previousl y normal ears compared with other groups (p = 0.008, Mann-Whitney U test). Conclusion: A pre-radiation therapy NPC tumor pattern was not found that cl early predicted the outcome of MEE after radiation treatment. The findings, however, suggest that approximately one third of MEEs in patients with inv asion of ET or paratubal structures, irrespective of the amount of ET displ acement, resolve after therapy. The MEEs that were present in ears with ET displacement and no invasion did not resolve despite reversal of the displa cement after treatment, which suggests that ET position plays a less import ant role than invasion in the resolution of MEE. It is, however, difficult to be certain, because ears with invasion were invariably associated with E T displacement, and the contribution of radiation therapy to the developmen t of MEE further complicates the issue.