Applications of the Grading Scales for the Detection of Ototoxicity in Children after Treatment of Neuroblastoma and Extracranial Germinal Tumor.

Introduction: Advances in treatment have resulted in a significant increase in survival rates for patients cured of malignant diseases such as neuroblastoma (NBL) and extracranial germ cell tumor (GCT). NBL is one of the pediatric cancers during which potentially ototoxic cytostatic drugs (cisplatin and carboplatin) are used for treatment. Other cancers include germinal tumors, hepatoblastoma, sarcomas, and brain tumors. Often, this very aggressive treatment has a high risk of causing long-term side effects, including hearing loss. Hence, the present study aimed to evaluate the usefulness of the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), Brock, Chang, and International Society of Pediatric Oncology (SIOP) Boston scales in terms of detecting the high-frequency nature of hearing loss induced by ototoxic drugs and monitoring hearing status in children after completion of oncological treatment. Additionally, the frequency of hearing loss in children treated for NBL and extracranial GCT was assessed, and the principles of monitoring hearing in these patients were indicated.

Methods: The study group consisted of 78 patients diagnosed with NBL (n = 47) and GCT (n = 31). There were 23 boys and 24 girls in the NBL group, aged 0-16 years, and 21 boys and 10 girls in the GCT group, aged 0-18 years. The control group consisted of 54 patients who had never received oncological treatment, were not taking potentially ototoxic drugs, and appeared socially efficient in the subjective audiological assessment. Audiometric examinations and DP-acoustic otoemission measurements were performed. Additionally, impedance audiometry tests were done to exclude a possible conductive component of the hearing loss.

Results: The analysis shows that ototoxicity-induced hearing loss was observed in 13.8-65.5% of children. 75.9% of patients showed hearing loss in the 16 kHz frequency range, and at least 56.8% of patients showed hearing loss in the frequency range above 12.5 kHz. Hearing impairment, relevant to speech understanding, was displayed by more than 40% of children treated for NBL and GCT.

Conclusions: The confirmation of hearing loss in nearly 65% of cases in both patients indicates the necessity to monitor the long-term side effects of anticancer treatment. Acoustic otoemission measurements, the adoption of articulatory indices based on an audiogram, or the use of arbitrary ototoxicity assessment scales such as Brock, Chang, or SIOP Boston are fully justified techniques for studying ototoxicity induced by cytostatic drugs. However, they all require continuous improvement to increase their sensitivity and specificity, especially in the pediatric group.