The treatment of childhood acute lymphocytic leukemia with prophylactic intrathecal and systemic intermediate-dose (150 mg/m²) methotrexate

A clinical study of 22 cases of childhood acute lymphocytic leukemia is reported. These patients were divided into a high risk group and a standard risk group (11 patients each). They were treated with vincristine and prednisone with or without L-asparaginase as induction followed by intrathecal methotrexate (MTX) as prophylaxis for central nervous system (CNS) leukemia, and then injection of intermediate-dose MTX was added while maintenance therapy with intrathecal MTX for 12 mo. The 5-yr survival rate was 0.905 in the standard risk group and 0.454 in the high risk group, and the 5-yr disease-free rate was 0.571 in the standard risk group, and 0.188 in the high risk group. High risk patients tended to relapse early and to die soon afterward, but standard risk patients tended to relapse late and even if they relapsed they responded well to re-induction therapy. No testicular involvement was seen. Only one out of 12 patients observed for more than 2-yr revealed mineralizing microangiopathy, without any clinical abnormalities. This protocol was effective in the standard risk group in preventing CNS leukemia, bone marrow relapse, and other extramedullary involvements, although the concentration of MTX in the cerebrospinal fluid was lower than 10^-7 M. However, in the high risk group, it was hardly effective at all in preventing CNS leukemia and bone marrow relapse.