Contribution of Chemotherapy Treatment Factors to Cognitive Outcomes in Survivors of Childhood Leukemia

Résumé

Long-term cognitive deficits are frequently observed in survivors of childhood acute lymphoblastic leukemia (ALL). Studies conducted in mice have identified chemotherapy agents methotrexate (MTX), dexamethasone (DEX) and prednisone (PRED) as having a significantly adverse impact on brain development. However, few studies have examined the relationship between variations in childhood exposure to these agents and cognitive abilities among ALL survivors. We hypothesized that survivors who had received higher doses of MTX would exhibit significantly greater cognitive impairments than survivors who received lower doses. Further, we hypothesized that survivors treated with both PRED and DEX will have greater cognitive deficits than those treated with DEX only. The sample included 59 ALL survivors (35 males, 24 females) between the ages of 8 and 18 years old. Compared to normed means, male ALL survivors exhibited significantly lower scores on working memory and processing speed, t(34) = -3.912, p<0.001 and t(34) = -5.077, p<0.001, respectively; female ALL survivors exhibited significantly lower scores on working memory, t(23)= -3.035, p<0.01. Variations in exposure to MTX, DEX and PRED were not correlated with variations in cognitive outcomes. Further research is needed to determine what factors explain different cognitive outcomes after chemotherapy treatment for childhood ALL.