Is high dose methotrexate without irradiation of the brain sufficiently effective in prevention of CNS disease in children with acute lymphoblastic leukemia?

We present 5-year results of treatment in 93 children suffering from acute lymphoblastic leukemia using two therapeutic protocols containing multidrug chemotherapy including high dose methotrexate. We could ascertain different results in standard and high risk patients. In a group of 62 children with standard risk we observed improvement in complete remission rate being 98.9% after induction phase of therapy, only one patient died on septicemia. Relapse rate in this group was 21.2% and that 14.7% in the bone marrow and 6.5% in CNS and no testicular relapse at all. In the group of 31 children with high risk leukemia all patients achieved complete remission. Only one of them died on acute pancreatitis due to toxicity. Overall relapse rate in this group was 28.9% with 12.8% of medullary relapse and 16.1% of CNS relapse. The last one was significantly higher than in the previous study when brain irradiation was a part of therapeutic procedure. It seems that this treatment is effective mainly in the standard risk leukemia, however, in the high risk leukemias this procedure appears to be less effective in preventing CNS leukemia. In this group of patients irradiation of the brain need to be enclosed in the therapy.