Outcome and Clinical Significance of Immunophenotypic Markers Expressed in Different Treatment Protocols of Pediatric Patients With T-ALL in Developing Countries.

Abstract

T-cell acute lymphoblastic leukemia (T-ALL) accounts for about 15% of pediatric ALL. With wider use of intensive chemotherapy, the prognosis for childhood T-ALL has improved. Further gains in treatment outcome will likely require methods to identify patients who continue to fail on contemporary protocols. This study aimed to evaluate pediatric patients with T-ALL at 2 different Arabic cancer centers regarding their clinicopathologic, immunophenotypic, and cytogenetic features and outcome. This retrospective study included all children with T-ALL treated between 2003 and 2013 at 2 oncology centers in the Middle East. Patients were divided into (group I) treated with Berlin-Frankfurt-Münster (BFM)-90 treatment protocol between February 2003 and June 2007 and (group II) includes all patients treated thereafter by the Total Therapy Study XIII protocol for high-risk ALL. This study included 103 patients with a median age of 8.9 years. The male to female ratio was 2.6:1. The median initial white blood cell count was 123× 109/L. Central nervous system leukemia was detected in 15%. The early T-cell precursor (ETP)-ALL phenotype was found in 16.5%. The 5-year overall survival was 20.7% ± 67.5% and 72.9% ± 5.7% (P< .01); the 5-year disease-free survival was 47.1% ± 13.8% and 77.3% ± 6.0% (P= .023); and the 5-year event-free survival was 28.6% ± 12.1% and 71.1% ± 6.2% (P= .003) for group I and II, respectively. The outcome of patients with T-ALL significantly improved in patients who received the treatment protocol of ALL with high-risk criteria. This protocol eliminates the bad outcomes effect of several clinical and immunophenotypic markers. Patient with the ETP-ALL phenotype had a nonsignificant inferior outcome compared with the non-ETP-ALL group.