 - Platinum derivatives and their toxicity Cisplatin, carboplatin, and oxaliplatin are major cytotoxic agents used in the treatment of many types of cancer. They exert their cytotoxic action by forming DNA adducts. However, their structural differences confer different pharmacokinetic and pharmacodynamic properties, and especially different toxicity profiles. Cisplatin induces a risk of nephrotoxicity at all ages, peripheral neuropathy of the extremities in young adults and a risk of ototoxicity in children. Carboplatin is essentially haematotoxic and sometimes ototoxic especially at high doses, while oxaliplatin is essentially neurotoxic. Ototoxicity is measured by pure-tone audiometry and is scored from grade 0 to grade 4, where grades 3 and 4 correspond to severe ototoxicity, according to the Brock grading system, the reference system for measuring ototoxicity at the time of treatment of these children and up until the present time Brock et al., 1991 Peters et al., 2000. Ototoxicity limits the cumulative dose of platinum derivatives in children. Cisplatin remains a major drug in paediatric oncology osteosarcoma, high-risk neuroblastoma, malignant germ cell tumours, hepatoblastoma, medulloblastoma, other brain tumours. Cisplatin ototoxicity is fairly frequent and can be very severe more than 50 of grade 1 or higher ototoxicity; 15 of grade 3 or 4 ototoxicity Bertolini et al., 2004. Carboplatin, an important component of the treatment of many embryonal tumours neuroblastoma, medulloblastoma, retinoblastoma is less frequently responsible for ototoxicity between 1 and 5 of grade 1 or higher ototoxicity, but can nevertheless occasionally cause serious ototoxicity 1 of grade 4 Jehanne et al., 2009. Ototoxicity can also appear and deteriorate for several years after treatment median time to discovery of carboplatin ototoxicity: 3.7 years, while no cases of recovery of high-grade hearing loss have been reported Bertolini et al., 2004; Jehanne et al., 2009. These ototoxicity phenomena can have very harmful consequences for the childs social development and schooling. Oxaliplatin will be excluded from this study, as few children are currently treated with this molecule, which is generally not ototoxic. 