Sensorineural Hearing Loss after Head-Neck Radiation Therapy

Objective: Sensorineural hearing loss (SNHL) has long been associated with radiation therapy (RT) for head and neck cancers (HNCa), but reporting criteria have been ill defined. The goal of this study was to evaluate the rate and severity of SNHL in HNCa patients receiving RT ± chemotherapy (chemo).

Method: Patients with audiometry pre- and post-RT for HNCa were retrospectively assessed using air and bone conduction thresholds for the pure tone average (PTA, 0.5, 1.0, 2.0 kHz) and 4 kHz. A 10 dB decrement at 2 consecutive evaluations separated by 6 months defined RT-induced SNHL.

Results: A total of 375 patients (750 ears) were evaluated. SNHL was observed at 4kHz in 246 ears (186 patients) and PTA in 79 ears (72 patients), over a median time of 2.7 (range, 0.3 -9.0) and 3.3 (range, 0.5-10) years, respectively. Cochlear dose and chemo were associated with onset of 4kHz SNHL (p60), gender, fractionation and fraction size were not. Five-year actuarial risk of 4kHz SNHL increased from 2% for doses 45 Gy to 52% for doses ≥ 45 Gy and from 39% for RT alone to 54% for chemo+RT.

Conclusion: Post-RT SNHL is more prevalent at higher frequencies and increases with RT dose received by cochlea as well as adjuvant chemo. Future studies on RT-induced SNHL should include high frequency bone conduction thresholds and account for cochlear dose and adjuvant therapy.