Korean J Pediatr.  2010 Nov;53(11):957-964. 10.3345/kjp.2010.53.11.957.

Prognostic significance of minimal residual disease detected by a simplified flow cytometric assay during remission induction chemotherapy in children with acute lymphoblastic leukemia

• Koh KN
• Park M
• Kim BE
• Im HJ
• Park CJ
• Jang S
• Chi HS
• Seo JJ

• KMID: 2280909
• DOI: http://doi.org/10.3345/kjp.2010.53.11.957

Abstract

BACKGROUND
Our study attempted to determine the prognostic significance of minimal residual disease (MRD) detected by a simplified flow cytometric assay during induction chemotherapy in children with B-cell acute lymphoblastic leukemia (B-ALL).
METHODS
A total of 98 patients were newly diagnosed with precursor B-ALL from June 2004 to December 2008 at the Asan Medical Center (Seoul, Korea). Of those, 37 were eligible for flow cytometric MRD study analysis on day 14 of their induction treatment. The flow cytometric MRD assay was based on the expression intensity of CD19/CD10/CD34 or aberrant expression of myeloid antigens by bone marrow nucleated cells.
RESULTS
Thirty-five patients (94.6%) had CD19-positive leukemic cells that also expressed CD10 and/or CD34, and 18 (48.6%) had leukemic cells with aberrant expression of myeloid antigens. Seven patients with > or =1% leukemic cells on day 14 had a significantly lower relapse-free survival (RFS) compared to the 30 patients with lower levels (42.9% [18.7%] vs. 92.0% [5.4%], P=0.004). Stratification into 3 MRD groups (> or =1%, 0.1-1%, and <0.1%) also showed a statistically significant difference in RFS (42.9% [18.7%] vs. 86.9% [8.7%] vs. 100%, P=0.013). However, the MRD status had no significant influence on overall survival. Multivariate analysis demonstrated that the MRD level on day 14 was an independent prognostic factor with borderline significance.
CONCLUSION
An MRD assay using simplified flow cytometry during induction chemotherapy may help to identify patients with B-ALL who have an excellent outcome and patients who are at higher risk for relapse.

Keyword

Lymphoblastic leukemia; Acute; Childhood; Minimal residual disease; Flow cytometry

MeSH Terms

B-Lymphocytes
Bone Marrow
Child
Flow Cytometry
Humans
Induction Chemotherapy
Multivariate Analysis
Neoplasm, Residual
Precursor Cell Lymphoblastic Leukemia-Lymphoma
Recurrence
Remission Induction