MIDDLE-EAR PRESSURES IN PATIENTS WITH NASOPHARYNGEAL CARCINOMA AND THEIR CLINICAL-SIGNIFICANCE

There is a paucity of studies investigating middle ear pressures (MEPs ) in patients with nasopharyngeal carcinoma (NPC). This paper prospect ively examines MEPs in patients with nasopharyngeal carcinoma before a nd after radiotherapy and discusses their clinical significance. Newly diagnosed patients with nasopharyngeal carcinoma were studied before and at three to 12 months (mean 7.5 months) after radiotherapy. MEPs w ere measured by tympanometry. Thirty-three patients completed the stud y. The mean MEP before and after radiotherapy was -55.2 mm water (rang e -250 to 45 mm water) and -73.1 mm water (range -215 to 35 mm water) respectively. About two-thirds of assessable ears had an increase in n egative MEPs after irradiation and the rest had less negative MEPs aft er irradiation. Those ears which developed post-irradiation middle ear effusions were found to have pre-irradiation negative middle ear pres sures of at least -45 mm water. These findings provide possible explan ations for some unexplained audiometric observations previously made i n patients with nasopharyngeal carcinoma after radiotherapy. Tympanome try before radiotherapy may prove to be useful in identifying ears wit h a high risk of developing post-irradiation middle ear effusion.