Caracterização do perfil neuropsicológico, acadêmico e comportamental de crianças e adolescentes sobreviventes de tumores de fossa posterior

Abstract

Cancer is the leading cause of death among Brazilian children, and 12.600 cases are estimated for 2017. Central nervous system (CNS) tumors are the most common on childhood, from which 60% arise in cerebellum or adjacent structures of posterior fossa. The lesion and treatment affect CNS functioning, and alterations in higher order functions have been related to the interruption of important connections between the cerebellum and cortical areas. Radiotherapy is responsible for increasing survivorship in malignant tumor cases, but it also promotes neurotoxic effects to the developing CNS. This study aimed to investigate neuropsychological and academic functioning in survivors of posterior fossa tumors. The research was subdivided into three studies: 1) Description of intellectual performance of pediatric patients diagnosed with posterior fossa tumors; 2) Investigation of executive functions in pediatric survivors of posterior fossa tumors and; 3) Proposal of a conceptual model to explain the neuropsychological profile of children and adolescents submitted to cranial radiation. 37 subjects aged 6-16 integrated clinical group, and 24 subjects formed a healthy control group matched 1:1 with the participants of studies 2 and 3 according to sex, age, type of school and socioeconomic level. Participants were submitted to neuropsychological evaluation and results were analyzed through descriptive and inferential statistical tools and clinic-qualitative analysis. In the first study, children who underwent radiotherapy had significantly lower performances on intellectual domains compared to children only surgically treated, mainly in nonverbal and processing speed domains. Nonverbal domain revealed significant differences according to treatment modality, while verbal domain led to significant differences according to mother educational level, which reveals a dissociation regarding to the domains more strongly affected by the tumor and the treatment, and the domains more affected by sociocultural factors. Children diagnosed later showed lower performances, which disagree with previous studies. The second study revealed executive impairments on both clinical groups in terms of working memory, inhibition, flexibility and planning. Children submitted to radiotherapy showed a broader range of affected domains and the most serious impairments compared to children who did not undergo radiotherapy. These children showed difficulties only in measures with more sophisticated executive demands, while children submitted to radiotherapy also presented impairments in more simple executive tasks. The third study presented important results towards the comprehension of the neuropsychological profile of children submitted to cranial radiation therapy. Data suggest that demyelination caused by radiotherapy leads to right hemisphere typical impairments, in a pattern which is similar to the Nonverbal Learning Disability (NLD) profile. Theoretical reflections resulting from data interpretation led to the proposition of a conceptual, comprehensive and systemic model as an explanation hypothesis to the emergency of childhood medulloblastoma neuropsychological profile. It is expected that this study encourage research interest towards the understanding of difficulties and challenges faced by this population, in order to contribute to the creation of public policies which enable children’s social and academic reinsertion after treatment, as well as to the creation of intervention programs which ensure the improvement of survivors’ quality of life.