Clinical Trials of CCLSG L874 and I874 Protocols without Cranial Irradiation for Standard-Risk Acute Lymphoblastic Leukemia in Childhood : A study from the Children's Cancer and Leukemia Study Group

Abstract

In the CCLSG-874 protocol for children with low-risk (LR) and intermediate-risk (IR) acute lymphoblastic leukemia (ALL), two regimens with or without cranial irradiation (CI) were compared with respect to their ability to prevent central nervous system (CNS) leukemia and to improve overall outcome of ALL. From 1987 to 1990, 82 and 109 evaluable patients were registered into L874 and I874 protocols for LR and IR patients, respectively. All responders to induction therapy were randomized to treatment with 18Gy of CI plus intrathecal methotrexate (MTX it) or to treatment with high-dose MTX plus MTX it. Patients were then treated with standard maintenance regimens of L874 and 1874. At a median follow-up of 39 months (range 14-58 months) there was no difference in the rate of hematologic relapse between the CI group and MTX group. The rate of CNS relapse in the MTX group seemed to be higher (3 of 39 in L874 and 2 of 54 in 1874) than that in the CI group (1 of 43 in L874 and 0 of 55 in 1874), but these data were not statistically significant. The rates of 4-year event-free survival (EFS) in L874 were 81.1±7.6% (mean±SE) and 75.2±7.9% (ns) for the CI and MTX group, respectively, and the rates of EFS in 1874 were 70.0±13.6% and 70.0±9.0% (ns) for the CI and MTX group, respectively. These data suggest that MTX alone may be as effective as CI to prolong diseasefree survival in LR and IR ALL although further continuous studies are needed. Analysis of serial CCLSG protocols for ALL from 1981 revealed that the rate of EFS of ALL allover including all risk groups has gradually been increasing from 44.2±3.6% for 811 protocol and 53.1±3.5% for 841 to 65.5±3.6% for the present 874 protocol.