Measuring the Neuro-Cognitive Side-Effects of Irradiation in Children with Brain Tumors

Background. Reduction of the treatment-related side effects has become one of the main goals of the recent study protocols for brain tumor therapies. When the treatment burden is decreased in patients with good prognostic features, the potential increased risk of relapse has to be counterbalanced by a significantly improved cognitive outcome. This objective is always clearly stated but comprehensive data on the neuropsychological outcomes are seldom reported. Procedures and Results. The appropriate means to measure the long-term morbidity need to be clarified. Health Status and Quality of Life (QOL) questionnaires can be easily administered but these questionnaires represent usually a composite evaluation where cognition is analyzed along with other items such as mood or pain. However, none of these questionnaires has ever been used to measure a difference in cognitive outcome when comparing two different therapeutic strategies in children. Complete neuropsychological evaluations are time consuming, need specialized psychologists and most of the tests have not been rigourously validated. In this respect, Wechsler scales are, however, robust and objective methods to evaluate intelligence. Several studies have been able to show meaningful differences in IQ scores between treatments in children with posterior fossa tumors, even with small numbers of patients. Conclusions. In order to evaluate any refinement in the treatment of these patients, widely accepted evaluation tools are needed. Ideally, these methods will have to be sensitive, reproducible, and widely applicable. None of the available tools fullfil all of these criteria but their development should be a major endeavour in modern neuro-oncology.