(A836) Incidence of Hearing Loss in Patients Treated with Immune Checkpoint Inhibitors

Introduction: Auditory dysfunction is a reported phenomenon with immune checkpoint inhibitor (ICI) therapy for advanced malignancy, but has only been studied in case reports and limited case series. Our objective was to investigate the incidence of ototoxicity secondary to ICI.

Methods: A retrospective study included patients treated with ICI at our tertiary care center between 2017 and 2022. Only patients with baseline and post-treatment audiograms were included. Patients with a history of platinum-based chemotherapy were excluded. Demographics, oncologic diagnosis, ICI treatment details, and temporal bone irradiation (TBRT) were recorded. Audiometric thresholds were compared before and after ICI therapy. The primary outcome measure was the incidence of hearing loss as defined by the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE). Secondary outcome measures included 1) incidence of hearing loss as defined by the American Speech-Language-Hearing Association (ASHA) criteria and the TUNE scale; and 2) patient factors associated with hearing loss. Statistical testing was completed with two-tailed t-tests and Chi square testing for continuous and ordinal data. Significance was set at p< 0.05.

Results: Out of 15,390 patients who received ICI between 2017 and 2022, 166 had baseline and post-treatment audiograms. Only 29 patients met inclusion criteria. Six of 29 patients (20.7%) experienced a CTCAE grade 1 or higher hearing loss. The incidence of hearing loss as defined by ASHA and TUNE criteria were 44.8% and 27.6%, respectively. The incidence of hearing loss was similar between patients who received TBRT and those who did not. The interval between audiograms was statistically associated with an increased incidence of hearing loss based on CTCAE criteria only (CTCAE: p = 0.02; ASHA: p = 0.07; TUNE: p = 0.45). None of the other potential covariates were significantly associated with the outcome.

Conclusions: Immune checkpoint inhibitors are potentially associated with a high incidence of hearing loss. Further research is needed to confirm these findings.