Neurotoxicity of treatment.

With the advent of effective treatment regimes increasing survival rates, delayed treatment-related cognitive dysfunction has been recognized as a significant problem. It is considered the most frequent complication among long-term survivors. WBRT may lead to deep brain atrophy and leukoencephalopathy associated with severe cognitive dysfunction, single-fraction dosages of greater than 2 Gy are related to an increased risk of late neurotoxicity, and other factors such as old age, concomitant chemotherapy and preexisting neurological disease increase this risk. However, the potential of focal radiotherapy (RT) with single dosages of 2 Gy or less to a maximal total dose of 60 Gy to produce significant neurotoxicity is less clear. There is a need for a concise neuropsychological test battery to be included in clinical trials, which should meet the following criteria: assess several domains found to be most sensitive to tumor and treatment effects, have standardized stimuli and administration procedures, have published normative data, have moderate to high test-retest reliability, have alternate forms or be relatively insensitive to practice effects, and therefore be suitable to monitor changes in cognitive function over time, include tests that have been translated into several Languages, which can be administered by a trained psychometrician or clinical research associate under supervision of a neuropsychologist, and have a relatively short total administration time. The neuropsychological domains to be evaluated should comprise the cognitive core deficit in brain-tumor patients, namely attention, executive functions (i.e., working memory, processing speed, sequencing abilities), verbal memory, and motor speed.