Allogeneic bone marrow transplantation versus chemotherapy for the treatment of childhood acute lymphoblastic leukemia in second remission: a single-institution study

Abstract

Purpose: A retrospective analysis of the treatment of childhood acute lymphoblastic leukemia (ALL) in second remission (CR2) was undertaken at our institution to compare the outcome and prognostic factors of patients treated with chemotherapy or allogeneic bone marrow transplantation (BMT).

Patients and methods: Seventy-five children who suffered a medullary relapse and achieved a second remission were treated with either an unmodified allogeneic HLA-matched sibling BMT after hyperfractionated total body irradiation (TBI) and cyclophosphamide (n = 38) or chemotherapy according to institutional chemotherapy protocols (n = 37). To avoid the bias of survival from the attainment of second remission in favor of BMT, the final comparative statistical analysis used the landmark approach and comprised 37 and 29 patients from the BMT and chemotherapy groups, respectively

Results: The disease-free survival (DFS) rate was 62% and 26% at 5 years, respectively, for the BMT and the chemotherapy groups (P = .03), with relapse rates of 19% and 67%, respectively, for these two groups (P = .01). There was an overall advantage for the BMT therapeutic approach, as compared with chemotherapy, for patients with ALL in CR2 (1) for patients with a WBC count (at diagnosis) of 20 x 10(9)/L or higher (DFS, 40% v 0%) and those with a WBC count of less than 20 x 10(9)/L (DFS, 73% v35%), (2) for patients whose duration of CR1 was less than 24 months (DFS 48% v 9%) and for patients whose duration of CR1 was 24 months or longer (DFS, 81% v 37%) and (3) for patients who were initially treated with intensive regimens incorporating more than five chemotherapy agents (DFS, 57% v 20%) and for patients treated with five agents or fewer (DFS, 72% v 32%).

Conclusion: In our single-institution series, unmodified HLA-matched allogeneic sibling transplants using hyperfractionated TBI and cyclophosphamide for patients with ALL in CR2 have resulted in superior outcome with a significantly improved probability of DFS and a lower relapse rate, as compared with those for patients treated with chemotherapy, regardless of the duration of first remission, the disease characteristics at diagnosis, or the intensity of prior treatment during first remission.