Long-term results in the treatment of acute nonlymphocytic leukemia: a Pediatric Oncology Group Study

Complete remission (CR), 5-year remission duration (RD), and overall 5-year survival rates are 74%, 28% and 25%, respectively, for previously untreated children with acute nonlymphocytic leukemia diagnosed between 1977 and 1981, following induction therapy with vincristine, doxorubicin and prednisone (VAP), consolidation therapy with 6-thioguanine, cytosine arabinoside (TA) and cyclophosphamide/vincristine/cytosine arabinoside/prednisone (COAP), and maintenance therapy of alternating TA and COAP with or without VAP pulses. Approximately 20% are free of their disease for more than 5 years. High white blood cell counts (WBC) at diagnosis and M3 and M6 morphology were associated with lower CR rates, while M5 morphology was associated with higher CR rates. Patients with M1 morphology had shorter remission duration as compared to those with M4 or M5 morphology. Low WBC and age between 2 and 10 years at diagnosis were associated with longer remission durations and survival. Patients with M4 morphology also survived longer. The observed CR rates are comparable to other studies initiated at the same time as this study but survival is less than those reported more recently. Low WBC at diagnosis and M4/M5 morphology may identify relatively favorable prognostic groups.