Audiometric outcomes for intravenous sodium thiosulfate for cisplatin-induced ototoxicity prevention in adults with head and neck cancer.

Abstract

e18110 Background: Cisplatin-induced ototoxicity (CIO) is a well-known complication of platinum-based chemotherapy that can cause hearing loss, substantially impairing quality of life, communication, and long-term survivorship. While sodium thiosulfate (STS; Pedmark) has demonstrated reduced rates of CIO in the pediatric population, there remains a critical evidence gap regarding its efficacy in adult pts with head and neck cancer (HNC). This study evaluates the effect of intravenous (IV) STS on audiometric outcomes in adult pts with HNC treated with cisplatin. Methods: A retrospective review of 7 adults (n=13 ears) with HNC treated for cure, planned cumulative cisplatin dose ≥150 mg/m², and treated between 11/2024-9/2025. 4/7 pts received chemoradiotherapy (CRT) with weekly cisplatin. 1 pt received cisplatin as part of induction therapy (IC) in addition to CRT and 3/7 received IC alone. According to FDA guidelines, IV STS was administered ≥6 hours after cisplatin completion, with a planned 1:1 cisplatin:STS dosing strategy. Conventional pure-tone audiometry was performed, including extended high-frequency testing and distortion product otoacoustic emissions (DPOAE). Primary endpoints included change in four-tone pure-tone averages (PTA; 500Hz, 1000Hz, 2000Hz, and 4000Hz) following initiation of treatment. Secondary outcomes included changes in extended high frequency PTA (ehfPTA; 9000Hz-20,000Hz) and DPOAE. Clinically significant hearing deterioration from baseline was defined as ≥10dB change in fPTA from baseline. Results: Of the 7 included patients (n=13 ears, 1 pt with prior unilateral sensorineural hearing loss), 57.1% were male (4/7), mean age of 51.1 years, and average cumulative cisplatin dose of 217.1mg/m 2 . The average time of last audiogram from initial cisplatin treatment was 73.4 days. There was no significant change in four-tone PTA from baseline to last audiogram (0.0dB) and there were no pts with clinically significant decline from baseline (0%, 0/7). 3 pts (n=6 ears) received comprehensive ehfPTA and DPOAE testing before and after treatment, with 1 ear (16.7%, 1/6) and 3 ears (50%, 3/6) experiencing a loss of response at highest baseline pure-tone threshold and DPOAE, respectively. Conclusions: Delayed IV STS was associated with preservation of clinically significant hearing in adults with HNC receiving curative-intent cisplatin, despite measurable changes on extended high-frequency audiometry and DPOAE testing. These findings support the use of comprehensive audiometric monitoring, including extended ehfPTA and DPOAE, to detect subclinical ototoxicity. The results extend the otoprotective paradigm established in pediatric oncology to the adult setting and suggest that STS is a feasible otoprotective strategy during platinum-based therapy. Prospective randomized studies with longer audiometric follow-up are warranted.