Purpose: We present a new ototoxicity grading system that has clearly defined and frequency-specific audiometric criteria. The purpose of this study was to validate this grading system by assessing its correspondence to audiology treatment recommendations and comparing it with the currently utilized Common Terminology Criteria for Adverse Events (CTCAE).
Patients and methods: A retrospective chart review was conducted using audiologic, demographic, and clinical data from 134 children receiving 149 courses of chemotherapy consisting of cisplatin and/or carboplatin. Pure-tone audiograms were evaluated using both our proposed grading criteria and the CTCAE criteria. The resulting grades were then compared with charted audiologic interventions and a number of clinical parameters to assess the clinical validity of the grading scale.
Results: Chang grade 2a or higher predicted audiologic intervention. Although both the Chang and CTCAE ototoxicity grades were significantly related to audiologist recommendations for assistive devices such as hearing aids and/or frequency modulated systems (P < .0001), the Chang scale was more specific, with the CTCAE scale diverging from clinical recommendation at higher grades. As expected, patients receiving cisplatin had more severe hearing loss with concurrent carboplatin administration, radiation therapy exposure, younger age, smaller body-surface area, longer treatment exposure, and more severe disease.
Conclusion: This grading system provides robust and clinically useful criteria to represent clinical hearing loss induced by ototoxicity with regard to the impact on speech and language and the need for assistive hearing devices. It is both more specific and more sensitive than the traditional CTCAE criteria for identifying clinically significant ototoxicity.