The long-term neuropsychological and adaptive outcomes of medullablastoma : impact of radiotherapy

Abstract

Brain tumours are the second most common form of childhood cancer. Medulloblastoma (MB) is a malignant posterior fossa brain tumour requiring surgery and radiotherapy while pilocytic astrocytoma (PA) is a benign posterior fossa brain tumour requiring surgery without radiotherapy. Both MB and PA occur predominantly during childhood. Literature shows the impact of radiotherapy (RT) on the neuropsychological functioning of MB survivors continues for at least five years posttreatment. However, research examining MB survivors beyond seven years posttreatment is very rare. Similarly, research available on the adaptive functioning, in particular coping and quality of life, experienced by survivors of posterior fossa tumours is limited. The current study observed the long-term neuropsychological and adaptive functioning outcomes of MB and PA survivors. Using a New Zealand sample of MB and PA survivors, comparisons were made between those who had radiotherapy post-surgery (MB; n=20) and those who had surgery alone (PA; n=19) to help identify the impact of RT on neuropsychological outcome and adaptive functioning (coping and quality of life). A control group demographically matched to the MB participants helped determine the overall impact of these posterior fossa tumours. Treatment variables and late effects were also examined. RT was found to have a profound long-term impact on the neuropsychological functioning of MB survivors; particularly in the areas of memory, attention, information processing speed, and executive functioning. The PA group who had surgery without RT also displayed deficits in these areas of neuropsychological functioning although to a lesser extent. Neuropsychological deficits did not, however, occur in the context of altered coping or reduced quality of life, except in the area of 'Learning'. Older age at diagnosis and increased time since surgery were related to better performance on neuropsychological tasks, while increased total number of treatment complications and late effects had a negative impact on neuropsychological performance. The findings are of relevance to rehabilitative therapy, and identifying expected deficit areas, and thereby allowing these to be targeted to improve level of functioning and quality of life.