A long-term clinical follow-up of children with acute lymphoblastic leukemia treated with intensive chemotherapy regimens.

One hundred and thirty-three children 15 years old and younger with acute lymphoblastic leukemia were treated with two different protocols. Both regimens consist of a multi-drug program, without CNS irradiation, administered for three years. Seventy-five children were enrolled on the first protocol, L-2; and 58 were treated on the subsequent regimen, L-10. Of the 70 evaluable patients on the L-2 program, 40 continue in complete remission from 72-111 months. Seventy-four percent of the children qualified for treatment cessation, and 59% have remained in continuous remission for six years. The estimated seven year disease-free survival for the 70 evaluable children on the L-2 protocol is 57% and for all entries is 53%. Of the 57 evaluable patients on the L-10 program, 35 are in complete remission from 15-67 months. The combined frequency of primary CNS leukemia for the two regimens is 7%. The off-therapy results of the L-2 protocol cannot be compared to the L-10 at present, but the on-therapy outcomes, despite the modifications that were designed to improve the L-10 regimen, are comparable.