Outcome of hematopoietic stem cell transplantation In refractory/relapsed infant leukemia

Abstract

PURPOSE/OBJECTIVE: Refractory/relapsed infant leukemia has an extremely poor prognosis. Whether hematopoietic stem cell transplantation (HSCT) can improve their outcome remains controversial. We reviewed our experience of HSCT on this group of patients. MATERIALS AND METHODS: This is a retrospective chart review on our HSCT patients’ cohort from Jan 1, 1995 to Dec 31, 2007. The indexed cases were identified from our HSCT electronic database from 1992 to 2007. RESULTS: Among >200 HSCT performed within this period, 8 patients with refractory/relapsed infant leukemia who underwent allogeneic HSCT were identified. Four patients had acute myeloid leukemia (AML); 2 had acute lymphoblastic leukemia (ALL); 1had juvenile myelomonocytic leukemia (JMML); and 1 had mixed lineage leukemia. Four patients had an initial white blood cell count >50_109/L, and 2 patients had cytogenetically detectable MLL rearrangement. For donor sources at first transplant, they were unrelated cord blood (n ? 1), unrelated bone marrow (BM, n ? 1) or related BM/peripheral blood stem cells (n ? 4). Three received busulphan/cyclophosphamide (AML) and one with busulphan/cyclophosphamide/melphalan (JMML) as conditioning and the other 4 had fludarabine based regimen with low dose irradiation. Seven patients achieved neutrophil engraftment at a median of 17 days (range: 13-22 days). Four patients relapsed after HSCT and 2 of them had upfront related HSCT. Despite second HSCT done in 2/4, all 4 of them died. Six patients experienced Grade III-IV acute graft versus host disease, and 5 (including the 2 with second transplant) developed various degree of hepatic venous-occlusive disease (VOD). Three patients (1ALL, 1AML & 1JMML) survived at 3, 8.8, and 13.8 years. The overall survival at 3 years was 37.5 +/- 17.1%. CONCLUSIONS: Despite having very poor prognosis, selected infants with refractory/relapsed leukemia could still be salvaged by allogeneic HSCT. We noted a high VOD and GvHD in our cohort so appropriate conditioning regimens should be adopted in the future.