We recognise that the sample size and hence the number of events were small and that this could have limited the statistical power to detect significant effects. Different treating centres made use of institutionally specific treatment protocols, often determined by resource constraints. Where space and bed capacity were at a premium, outpatient approaches, like JEb was favoured over inpatient regimens like BEP or PEb. Also age cut offs for the admission of adolescents to paediatric wards varied widely between POUs, resulting in an under-representation of older adolescents (16-19 years). Additionally, access to formal radio-isotope testing and audiology testing was fragmented, limiting the accurate assessment of renal function for platin dosing and hearing assessments.