A retrospective study of paediatric hearing loss in cranial radiotherapy combined with platin-based chemotherapy

Objective: Cranial Radiotherapy (CRT) is a common aspect of treatment for brain tumours in childhood. Larger cochlear dose of radiation correlates with greater hearing loss (eg. Hua et al., 2008), especially in combination with Cisplatin chemotherapy (eg. Paulinho et al, 2010). Animal studies and clinical studies in adults suggest asymmetrical hearing loss (Miller et al., 2007; Van der Putten, 2006).Materials and Methods: We initiated a retrospective study in a pediatric population with brain tumours to investigate the effects of CRT on audiological thresholds, as part of our involvement in PANCare-Life. Initial results include a comparison of post-chemotherapy thresholds of 186 patients (57 who had CRT, 129 who did not) to investigate progressive audiological changes after cessation of platin treatment. Thresholds were categorized according to the Münster system, focusing on minimal high-frequency changes (Schmidt et al., 2007).Results: The CRT and non-CRT groups were characterized by asymmetrical vs symmetrical post-treatment hearing losses respectively. A robust tendency (p= 0.05, Fisher's exact) towards asymmetrical deterioration was found in the CRT group. No significant differences were found in the estimated mean cochlear dose of CRT per ear (means of 42.5 and 47 Gy (t=0.18) for the least and most irradiated ears respectively) given to a group of 19 CRT patients. Inter-ear hearing thresholds for this group also showed no significant difference which, although it does not directly support the idea of asymmetrical cranial radiation as a cause of increased asymmetrical hearing loss (Van den Putten, 2006), does take a complimentary position.Conclusion: These findings underline the necessity of audiological follow up after cessation of platin therapy, especially in children with combined cranial irradiation.