RISK-FACTORS FOR INTELLECTUAL AND EDUCATIONAL SEQUELAE OF CRANIAL IRRADIATION IN CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA

Long-term cognitive and educational sequelae have been inconsistently reported in children who received cranial irradiation (CRT) to prevent central nervous system (CNS) disease in acute lymphoblastic leukaemia (ALL). This study investigates a large and representative sample of s urvivors of ALL and compares them with non-irradiated survivors of can cer and healthy control children to determine the effect of CRT on cog nitive and educational ability. Three groups of children were studied: Group 1 (n = 100) survivors of ALL treated with chemotherapy and CRT, group 2 (n=50) children with a variety of malignancies treated with c hemotherapy alone, group 3 (n=100) healthy children. Cognitive and edu cational abilities of these groups were evalutated using standardised psychometric techniques. Significant differences in cognitive and educ ational abilities were found between the children in group 1 (chemothe rapy + CRT) and the two control groups, with the children receiving CR T performing less well in a range of tests. Greatest differences were detected for tasks dependent on language function including verbal IQ, reading and spelling. Within group 1 a younger age at treatment (less than 5 years) and a higher dose of CRT (24 Gy vs 18 Gy) were predicti ve of poor long-term outcome for cognitive and education ability. In c ontrast, children who received chemotherapy alone, with or without int rathecal methotrexate, performed similarly to healthy controls. No gen der differences were detected for these measures.