Progressive neurocognitive impairment in young adult survivors of childhood acute lymphoblastic leukemia.

Background: Despite the extensive literature on neuropsychological sequelae after treatment of childhood acute lymphoblastic leukemia (ALL), the very-long-term neurocognitive outcome of the survivors is poorly studied. We assessed neuropsychological functioning in a population-based cohort of young adult childhood ALL survivors.

Procedure: Neuropsychological testing was performed on 64 survivors an average of 20 years after the diagnosis. The test battery included verbal intelligence quotient (VIQ) and performance intelligence quotient (PIQ), memory function, orientation and attention as well as motor performance. Cranial irradiation had been administered to 44 survivors as part of ALL treatment, whereas 20 survivors had been treated solely with chemotherapy. A control group consisted of 45 healthy young adults. Earlier neuropsychological test results of 45 of the survivors were available for comparison.

Results: The ALL survivors attained significantly lower test scores than the controls in all the neuropsychological function areas. The mean VIQ test scores were 91, 100, and 109 (P < 0.001), and the mean PIQ test scores 100, 111, and 118 (P < 0.001) for the irradiated survivors, non-irradiated survivors and controls, respectively. Memory and motor functions were impaired among the irradiated survivor group compared with the controls. A significant decline in PIQ and VIQ test scores was observed in the irradiated survivor group during the follow-up period, but only in VIQ in the non-irradiated group.

Conclusions: Survivors of childhood ALL suffer from long-lasting progressive neuropsychological impairment, especially when treatment includes cranial irradiation.