Long-term results of the pediatric oncology group studies for childhood acute lymphoblastic leukemia 1984-2001: A report from the children's oncology group

From 1984 to 2001, the Pediatric Oncology Group (POG) conducted 12 acute lymphoblastic leukemia (ALL) studies. Ten-year event-free survival (EFS) for patients >12 months of age with B-precursor ALL on acute leukemia in children 14, 15 and 16 series were 66.7±1.2%, 68.1±1.4% and 73.2±2.1%, respectively. Intermediate dose methotrexate (ID MTX; 1 g/m²) improved outcomes for standard risk patients (10-year EFS 77.5±2.7% vs 66.3±3.1% for oral MTX). Neither MTX intensification (2.5 g/m²) nor addition of cytosine arabinoside/daunomycin/teniposide improved outcomes for higher risk patients. Intermediate dose mercaptopurine (1 g/m ²) failed to improve outcomes for either group. Ten-year EFS for patients with T-cell ALL, POG 8704 and 9404 were 49.1±3.1% and 72.2±4.7%, respectively. Intensive asparaginase (10-year EFS 61.8 vs 42.7%) and high-dose MTX (5 g/m 2) (10-year EFS 78.0 vs 65.8%) improved outcomes. There was a non-significant improvement in EFS for infants (10-year EFS 17.7±7.2-31.9±8.3%). Prognostic indicators for B-precursor ALL were age and WBC at diagnosis, gender, central nervous system disease, DNA index and cytogenetic abnormalities. Only gender was prognostic in T-cell ALL. In infants, WBC and MLL translocation were linked to inferior outcome.