ASSOCIATION OF 1800 CGY CRANIAL IRRADIATION WITH INTELLECTUAL FUNCTION IN CHILDREN WITH ACUTE LYMPHOBLASTIC-LEUKEMIA

Cranial radiation therapy in childhood acute lymphoblastic leukaemia h as been associated with adverse neuropsychological effects, such as lo w intelligence. However, records show that these associations usually occur when the dose of radiation used is 2400 cGy. We investigated whe ther a lower dose of 1800 cGy had the same adverse effects on long-ter m survivors and whether high doses of methotrexate but no radiation th erapy would have a more beneficial effect. We evaluated 203 children f or six years in a multi-centre European study. The patients were divid ed into two groups: 129 children treated with 1800 cGy of cranial radi ation therapy and 74 children who received high-dose methotrexate but no radiation therapy. We used full scale intelligence quotient, verbal , and performance IQ tests to assess the patient's intelligence. We fo und a significant decline in full scale intelligence quotient in the i rradiated group that increased with the length of time from diagnosis. Younger age at diagnosis was associated with lower full scale intelli gence quotient in the radiated group.Our results indicate that a radia tion dose of 1800 cGy can have negative effects on neurocognitive func tion and we continue to question the benefit of low-dose cranial radia tion therapy.