Abstract
A total of 193 children, registered as standard-risk ALL, were treated by protocols designated as AL841 (62 cases), LR90 (74) and IR90 (57). Using vincristine, prednisolone, L-asparaginase± daunomycin, 191 cases (99%) achieved complete remission. After consolidation with intermediate doses of methotrexate (MTX) ± BFM type intensification, all cases received modified LSA2-L2 type cyclic maintenance therapy for 2-3 years. As prophylaxis for central nervous system (CNS) leukemia, intrathecal MTX and cranial irradiation (18 Gy for AL841, 0 Gy for LR90 and 15 Gy for IR90) were used. As of August, 1995, (median follow-up duration of 90, 37 and 32 months for AL841, LR90 and IR90, respectively), 30 cases (10 in each protocol) developed relapse, 10 of which occurred after discontinuation of therapy. Relapse sites were bone marrow (20 cases), extramedullary (9 including 5 isolated CNS) and a combination of both (one). Four-year event-free survival (EFS) and overall survival (OS) with AL841, LR90 and IR90 were 85%±4.9%, 75%±7.1%, 73%±7.1%, and 94%±3.1%, 85%±5.9%, 87%±5.6%, respectively. Ten-year EFS and OS for AL841 were 82%±5.0% and 89%±4.0%. EFSs of each protocol were analysed by various known risk factors, none of which showed statistical significance. In AL841 and LR90, the best 4-year EFSs of 93%±6.4% and 80%±10% were found among subgroups of cases which presented with initial WBC counts of between 5, 000 and 10, 000/μ1. Other modalities indentifying new risk factors must be explored in the treatment of standard-risk ALL for breakthrough improvement of EFS.
