NEUROPSYCHOLOGICAL FUNCTION IN ADULTS AFTER HIGH-DOSE FRACTIONATED RADIATION-THERAPY OF SKULL BASE TUMORS

Purpose: To evaluate the long term effects of high dose fractionated r adiation therapy on brain functioning prospectively in adults without primary brain tumors. Methods and Materials: Seventeen patients with h istologically confirmed chordomas and low grade chondrosarcomas of the skull base were evaluated with neuropsychological measures of intelli gence, language, memory, attention, motor function and mood following surgical resection/biopsy of the tumor prior to irradiation, and then at about 6 months, 2 years and 4 years following completion of treatme nt, None received chemotherapy. Results: In the patients without tumor recurrence or radiation necrosis, there were no indications of advers e effects on cognitive functioning in the post-acute through the late stages after brain irradiation, Even in patients who received doses of radiation up to 66 Cobalt Gy equivalent through nondiseased (temporal lobe) brain tissue, memory and cognitive functioning remained stable for up to 5 years after treatment, A mild decline in psychomotor speed was seen in more than half of the patients, and motor slowing was rel ated to higher radiation doses in midline and temporal lobe brain stru ctures. Conclusion: Results suggest that in adults, tolerance for focu sed radiation is relatively high in cortical brain structures. (C) 199 7 Elsevier Science Inc.