An update of the results of intensive therapy in children with acute lymphoblastic leukemia.

On January 1984 a protocol for newly diagnosed children with acute lymphoblastic leukemia started in a multiinstitutional setting in Argentina, Costa Rica and Cuba. The protocol was based on the BFM 76/79 study. It consisted in 8 drug 8 weeks induction-consolidation regimen with a delayed intensification regimen followed by maintenance with 6-mercaptopurine-methotrexate and pulses with vincristine-prednisone for 36 months. CNS prophylaxis with IT therapy, age based schedule was given. Only patients with greater than 50000 WBC counts received cranial irradiation. A total of 720 patients were registered up to June 1987, 703 of them were eligible. Six hundred an twenty six (89%) of the patients achieved complete remission, 7 partial remission, 8 failed to respond and 62 (9%) had drug or disease related death before completing induction therapy. At 72 months 50% remained in complete remission, 45% and 58% of all the patients remained disease-free and alive respectively. Sites of relapse were bone marrow 21%, CNS 10%, testis 2%, combined 4% and 8% died in complete remission. No difference in response was observed among the three prognostic groups, however the disease-free survival at 72 months was 52% for good prognosis compared to 42% for intermediate and poor prognosis (P = 0.0009). This results showed a marked improvement over previous studies of our group and, that, intensive and large clinical trials can be performed in Latinamerica.