Comparison of CNS Relapse, Survival and Intelligent Quotient in Non-High Risk ALL Children Treated with Intrathecal Methotrexate or Triple Intrathecal Therapy

Compared to intrathecal methotrexate (IT MTX), triple intrathecal therapy (TIT) has shown promising results in decreasing central nervous system (CNS) relapse in children with acute lymphoblastic leukemia (ALL). We aimed to compare these two IT regimens in terms of CNS relapse, survival, and IQ in Iranian non-high risk ALL children. In a two phases clinical trial study, 203 children with non-high risk ALL, aged 1-10 years at diagnosis, who were previously treated with the same systemic protocol but with two different IT regimens, based on IT regimen allocated to IT MTX (n = 109) and TIT (n = 84) groups were studied. In phase 1, isolated CNS relapses (i-CNS) and five-year survival of the two groups was compared, and in phase 2, IQ score of survivors of two groups was measured and compared. The overall rate of i-CNS relapse was 13.8% and the incidence of i-CNS relapse in contrast to other areas in the IT MTX group, was higher than in the TIT group (17.4% vs. 9.6%; P= 0.03). Most i-CNS relapses were asymptomatic and "early" and there was no significant relation between IT formulation and secondary relapse and mortality rate in patients with i-CNS relapse (P> 0.05). The 5-year survival of TIT group was more than the IT MTX group (80.9% vs.70.6%; P=0.04), but the mean scores of full-scale, verbal, and performance IQ (except cubes) were not significantly different in the two groups. Based on the results, TIT regimen compared to IT MTX reduced i-CNS relapse and increased 5-year survival in Iranian children with ALL but had no significant differences in total IQ score.