Prevalence of hearing loss and tinnitus after childhood cancer treatment: a Danish nationwide registry-based study.

BACKGROUND: Despite rising survival rates and high-quality health data available - no large-scale study has mapped the full Danish Childhood Cancer Survivor population with auditory late effects. AIMS/OBJECTIVES: This study aimed to estimate the prevalence of auditory late effects among Danish children and adolescents diagnosed with cancer in a national register-based study. MATERIALS AND METHODS: Using data from the Danish Cancer Register and the Danish National Patient Register, we identified children diagnosed with cancer before the age of 18 between 2014 and 2024. Statistical analyses including descriptive statistics, chi-square tests, relative risks and trend analysis were performed to explore patterns and potential associations between cancer diagnosis and the development of auditory late effects. RESULTS: The study population consisted of 3075 children with a registration in the Danish Cancer Register. The prevalence of auditory late effects was 5.7%. The risk was higher among younger patients, patients with malignant neoplasms and patients receiving high-dose chemotherapy at a younger age.. CONCLUSION AND SIGNIFICANCE: These findings highlight auditory late effects as a relevant late effect with implications for quality of life. Early identification and monitoring are essential to support developmental outcomes, particularly in younger patients, and to increase awareness in survivorship care.