Long-term audiologic follow-up of carboplatin-treated children with retinoblastoma

Background: Children treated for retinoblastoma with carboplatin have an increased risk for ototoxicity. Impaired hearing may have major consequences for these children, because they often suffer from reduced vision. Previous studies have shown limited information on the incidence and severity of carboplatin-induced ototoxicity and the used audiologic methods. The frequency of audiological testing is often limited and the audiologic follow-up time is relatively short. Objective: The aim of this study was to determine the long-term effects of carboplatin ototoxicity in children with retinoblastoma. Materials and methods: In this retrospective non-randomized single center cohort study, we reviewed audiologic results of 25 patients. Experienced audiologists analyzed the pure-tone audiograms. Results: All patients had normal hearing prior to therapy and had a mean age of 11 months at first carboplatin administration. The mean audiologic follow-up was 12.0 years with a median of 11.6 (IQR 4.8) years. Three patients were excluded: two passed away and one could not participate in the audiologic tests. One of the 22 included patients developed sustained low-grade bilateral highfrequency hearing loss between 2 and 7 years after the last carboplatin dose. In one patient it was not possible to make a reliable conclusion due to a conductive hearing loss component. Twenty patients had normal hearing. Conclusions: We observed no clear effect between carboplatin administration in young children and clinical significant ototoxicity in the long term. One child showed low-grade bilateral high-frequency hearing loss.