Memory Neuroimaging in Children, Adolescents and Young Adults Following Pediatric Cancer

Brain tumours are the leading cause of cancer-related death and morbidity in children, adolescents and young adults. The brain is also one of the most sensitive organs to treatments used in pediatric oncology, even for cancers not related to the central nervous system. Therapeutic index is therefore a major issue in pediatric neuro-oncology. The efficacy of the therapy as well as its toxicity are difficult to measure using standard tests. In order to optimize therapies that could have an impact on the brain, and consequently on the quality of life of patients, it becomes crucial to optimize the means of evaluation. Few studies to date have focused on the various components of memory impacted following treatment of a posterior fossa tumour. However, supra-tentorial structures such as the hippocampus, which have long been described for their role in memory, are either partially irradiated (irradiated in their lower part due to their proximity to the target volume during irradiation of the posterior fossa) or completely irradiated (e.g. included in the prophylactic irradiation of medulloblastoma prior to dose supplementation in the posterior fossa). On the other hand, the cerebellum plays a central role in learning and procedural memory involved in motor and cognitive learning, as it enables automation and procedural retention such as reading (automation of the grapho-phonemic conversion procedure) or arithmetic (mental arithmetic). IMPALA study is aimed at investigating the impact of different irradiation doses received by children treated with radiotherapy on cognitive functions related to the hippocampus and to the cerebellum. This exploratory study will thus provide elements enabling a better limitation of radiotherapy doses on regions linked to the development of cognition and memory. The project brings together researchers and clinicians with complementary expertise in oncology, neurology and imaging in both children and adults. This study will also provide a