Sensorineural Hearing Loss After Radiotherapy and Chemoradiotherapy: A Single, Blinded, Randomized Study

Abstract

The synergistic ototoxicity of radiation and cisplatin (CDDP) has not been adequately studied. This study investigated whether the use of concurrent and postradiotherapy CDDP in patients with nasopharyngeal carcinoma (NPC) resulted in a difference in postradiotherapy sensorineural hearing when compared with the use of radiotherapy alone. Newly diagnosed patients were randomly assigned to the radiotherapy or chemoradiotherapy groups. Bone conduction hearing thresholds were performed before treatment and at 1 week, 6 months, 1 year, and 2 years after completion of radiotherapy. Statistical analysis was performed using the Mann-Whitney U test. Hearing thresholds averaged over 0.5, 1, and 2 kHz were found to be poorer in the chemoradiotherapy group (58 patients) compared with the radiotherapy group (57 patients) at 1 year (P = .001) and 2 years (P = .03) after radiotherapy. Hearing thresholds at 4 kHz were significantly worse for patients in the chemoradiotherapy arm at all of the postradiotherapy time points studied and were more severely affected than the thresholds at lower speech frequencies. In the radiotherapy group, deterioration of median hearing thresholds, which occurred in the immediate post-treatment period, improved within the first year but deteriorated again at 2 years. In the chemoradiotherapy group, median hearing threshold deterioration, which started immediately after radiotherapy, stabilized by 1 year. Patients with NPC who received radiotherapy and concurrent/adjuvant chemotherapy using CDDP experienced greater sensorineural hearing loss compared with patients treated with radiotherapy alone, especially to high-frequency sounds in the speech range. Normal inner ear tissue tolerance, which was once defined only for radiotherapy patients alone, should be redefined in chemoradiotherapy patients.