Audiometric Monitoring and Its Determinants in Patients Undergoing Chemoradiotherapy for Head and Neck Cancer.

BACKGROUND AND OBJECTIVES: Audiometric monitoring is recommended for patients receiving ototoxic (chemo)radiotherapy for head and neck cancer (HNC), yet real-world uptake is poorly characterized and potentially inequitable. We quantified the uptake and timing of audiometric testing and examined rural-urban residence and age as candidate determinants. MATERIALS AND METHODS: We conducted a single-center retrospective cohort study of 70 consecutive patients with HNC treated with radiotherapy between November 2024 and September 2025, comparing rural (n = 32) and urban (n = 38) residents. Outcomes were audiometric testing at treatment initiation, repeat audiometry during follow-up, and post-treatment hearing change. Analyses included Fisher's exact and Mann-Whitney U tests, Spearman correlations, Firth-penalized logistic regression, inverse probability of treatment weighting (IPTW), restricted cubic splines, and sensitivity analyses. RESULTS: Audiometry at treatment initiation was performed in 31/70 patients (44.3%) and repeat audiometry in only 10/70 (14.3%); among tested patients with documented dates, just 19.4% underwent audiometry before the first radiotherapy fraction, so that a true pre-exposure baseline existed for only 6/70 patients (8.6%). Uptake at initiation was 53.7% with concurrent cisplatin, 14.3% with carboplatin, and 36.4% with radiotherapy alone (p = 0.114). Uptake did not differ by residence (rural 40.6% vs. urban 47.4%; odds ratio (OR) 0.76, 95% confidence interval (CI) 0.30-1.96, p = 0.634), with an IPTW-weighted risk difference of -9.9% (95% CI -30.9 to +11.8). Age was the dominant determinant: uptake fell from 90.5% below 65 years to 24.5% at ≥65 years (adjusted OR per decade 0.32, 95% CI 0.15-0.71, p = 0.005), with significant non-linearity (p = 0.015). Pre-existing hearing loss was associated with lower testing (OR 0.29, 95% CI 0.10-0.91, p = 0.032). Post-treatment hearing change occurred in 54.3% overall (rural 46.9% vs. urban 60.5%, p = 0.336), comprising a subjective hearing complaint in 51.4% and audiometric deterioration in six of the nine patients with paired audiograms. CONCLUSIONS: Audiometric monitoring was incomplete, rarely obtained before irradiation, and steeply age-patterned, whereas rural residence was not associated with lower uptake; structured, exposure-based referral pathways, triggered by planned cisplatin and clinically relevant cochlear dose and applied irrespective of age, are warranted.