Clinical Characteristics and Treatment Outcome of Infantile Acute Lymphoblastic Leukemia

Cho, Hwa Jin; Han, Dong Kyun; Baek, Hee Jo; Park, Eun Young; Lee, Soon Ju; Kook, Hoon; Hwang, Tai Ju

Abstract

PURPOSE: Acute lymphoblastic leukemia (ALL) in infancy accounts for about 2~4% cases of childhood ALL and is biologically different from that of older children with an extremely poor prognosis. The optimal treatment and the role of stem cell transplantation (SCT) are controversial. The aim of this study was to characterize ALL in infancy and to explore the efficacy of intensified chemotherapy and SCT.
METHODS
The author retrospectively reviewed the clinical findings of the 13 infant who were treated for ALL at Chonnam National University Hospital between 1995 and 2008. They were 6 boys and 7 girls. The median age was 5.9 months (range: 1~10 months). Six infants underwent SCT following conditioning regimen: Busulfan (Bu)-based, 4; TBI-based, 2. Disease status at transplant was complete remission (CR) 1 in 5, CR2 in 1. The source of stem cells were BM (n=3), PBSCs (n=2), and UCB (n=1).
RESULTS
The presenting symptoms were abdominal distension, fever, bruising and pallor. Marked leukocytosis (median WBC, 157,600/microL), anemia (median Hgb, 6.8 g/dL) and thrombocytopenia (median PLT, 28,500/microL) were noted. Seven patients (53.8%) had initial CNS involvement. By immunophenotyping, 9 had CD10(+) early precursor B-cell, 2 had CD10+ precursor B-cell, and the remaining 2 had T-cell phenotype. No patients had myeloid co-expression. MLL gene rearrangement was positive in 7 of 10 patients by FISH. Among them, 2 had MLL/AF4(+) by RT-PCR, and 6 had t(4;11)(q21:23) by cytogenetics. One patient did not receive treatment against medical advice. Ten of 12 patients (83.3%) achieved remission after induction chemotherapy. Two patients died during induction chemotherapy: acute renal failure (1), Candida glabrata pneumonia (1). Three patients died during consolidation chemotherapy: ARDS due to parainfluenza 3 infection, sepsis, and asphyxia. The median interval between the diagnosis and SCT was 5 months (range: 4~7). No graft failure occurred. Acute GvHD was found in 3 (Grade II, 1; Grade IV, 2), but none had chronic GvHD. Four patients died after transplant: acute GvHD, ARDS, severe bleeding, and invasive pulmonary aspergillosis. Three-year Kaplan-Meier event free survival of all patients was 23%.
CONCLUSION
Infant ALL is characterized by hyperleukocytosis, hepatosplenomegaly, CNS involvement, CD10 negativity and MLL gene rearrangements. Although all survivors achieved CR after chemotherapy, the 3 year-EFS was only 23%, even SCT was done in 6. The treatment failure was mainly due to infections, hemorrhage and transplant-related mortality rather than the recurrence of the disease. These results shows that better supportive therapy and prevention of these complications may improve the treatment outcomes. Optimal consolidation strategies such as SCT and targeted therapy following remission induction along with better supportive care should be pursed through nation-wide prospective, multicenter studies.