Efficacy of Intratympanic Sodium Thiosulfate Gel Injection to Prevent Cisplatin‐Induced Ototoxicity

OBJECTIVE: This study aimed to evaluate the efficacy and safety of intratympanic sodium thiosulfate (STS) gel injection in preventing cisplatin-induced hearing loss. METHODS: We conducted a single-blinded randomized controlled trial, enrolling adults with head and neck cancer undergoing cisplatin chemotherapy. Intratympanic STS gel was injected into one ear within 3 h before each cisplatin cycle, while the contralateral ear served as a control. Clinical and audiometric assessments were performed before each injection and 1-3 months after the completion of chemotherapy. Changes in hearing thresholds from baseline at each frequency were measured. Ototoxicity was defined according to the American Speech-Language-Hearing Association (ASHA) criteria. Adverse events associated with intratympanic STS gel injections were also monitored. RESULTS: Twenty-eight patients were included in the study. Based on ASHA criteria within the frequency range of 0.25-8 kHz, there was no statistically significant difference in the incidence of ototoxicity between the treated and control ears (p = 0.683). Compared with control ears, treated ears exhibited significantly reduced threshold shifts from baseline in the 4, 6, 8, 9, and 11 kHz, with mean differences of approximately 7-10 dB. A safety analysis of 74 injections revealed minor adverse effects, including otalgia (10.8%), transient vertigo (10.8%), dizziness (14.8%), and tympanic membrane perforation (4.0%). CONCLUSION: Our findings showed no significant difference in the incidence of cisplatin ototoxicity between STS injected and control ears. Nonetheless, intratympanic STS gel injections demonstrated potential benefits in preserving hearing at high and extended-high frequencies. The procedure was generally well-tolerated, with manageable adverse effects. LEVEL OF EVIDENCE: N/A.