Outcome of Childhood Acute Myeloid Leukemia With FLT3-ITD Mutation: The Experience of Children's Cancer Hospital Egypt, 2007-17

Acute promyelocytic leukemia in children cancer hospital Egypt

BACKGROUND

Pediatric acute promyelocytic leukemia (APL) accounts for 5 to 15% of all myelocytic leukemia. A retrospective analysis of pediatric patients diagnosed and treated with APL was conducted at CCHE from July 2012 to the end of December 2019, to report the prevalence, clinical characteristics, results, and risk factors associated with induction failure and early death.

RESULT

Sixty-two patients were reported, with an age greater than ten, an initial poor coagulation profile, and a total leukocyte count (TLC) greater than 30 103/mm3 influencing 5-year overall (OS) and event-free survival (EFS), as well as a high promyelocyte count affecting 5-year EFS. Patients received a regimen based on the COG AAML0631 protocol. High-risk patients with an initial TLC > 10 × 103/mm3 and an initial promyelocytic count of 30% or more with a substantial P-value are prognostic markers for early death during induction. In females, wild FLT3 increases the risk of differentiation syndrome (DS). Receiving steroids with all-trans retinoic acid (ATRA) induction may reduce the occurrence of DS. Relapse alters the outcome. In the current study, 45 patients are alive in complete remission, with a 5-year OS of 72.5% and a 5-year EFS of 69.4%, respectively.

CONCLUSION

Pediatric APL outcomes are influenced by age above 10, an initial poor coagulation profile, and a promyelocyte count of more than 10%. An initial leukocyte count of more than 10 × 103/mm and an initial promyelocytic count of more than 30% increase the risk of early death. Receiving steroids with ATRA may reduce the occurrence of DS.

Characteristics and Outcome of FLT3-ITD-Positive Pediatric Acute Myeloid Leukemia-Experience of Polish Pediatric Leukemia and Lymphoma Study Group from 2005 to 2022

BACKGROUND

The FMS-like tyrosine kinase 3 (FLT3) gene mutated in 10-15% of pediatric acute myeloid leukemia (AML) is associated with an inferior outcome. The aim of the study was to analyze the outcome and characteristics of FLT3-ITD-positive pediatric AML.

METHODS

We retrospectively analyzed the nationwide pediatric AML database from between 2005 and 2022. FLT3-ITD was found in 54/497 (10.7%) patients with available analysis. Three consecutive treatment protocols were used (AML-BFM 2004 Interim, AML-BFM 2012 Registry, AML-BFM 2019 recommendations).

RESULTS

Probabilities of 5-year overall (OS), event-free (EFS) and relapse-free survival were significantly lower in the FLT3-ITD-positive patients compared to FLT3-ITD-negative (0.54 vs. 0.71, p = 0.041; 0.36 vs. 0.59, p = 0.0004; 0.47 vs. 0.70, p = 0.0029, accordingly). An improvement in the outcome was found in the analyzed period of time, with a trend of better survival in patients treated under the AML-BFM 2012 and AML-BFM 2019 protocols compared to the AML-BFM 2004 protocol (5-year EFS 0.52 vs. 0.27, p = 0.069). There was a trend of improved outcomes in patients treated with FLT3 inhibitors (n = 9, 2-year EFS 0.67 vs. 0.33, p = 0.053) and those who received stem cell transplantation (SCT) (n = 26; 5-year EFS 0.70 vs. 0.27, p = 0.059). The co-occurrence of the WT1 mutation had a dismal impact on the prognosis (5-year EFS 0.23 vs. 0.69, p = 0.002), while the NPM1 mutation improved survival (5-year OS 1.0 vs. 0.44, p = 0.036).

CONCLUSIONS

It seems that SCT and FLT3 inhibitors have a beneficial impact on the prognosis. Additional genetic alterations, like the WT1 and NPM1 mutations, significantly influence the outcome.

Molecular dissection of a hyper-aggressive CBFB-MYH11/FLT3-ITD-positive acute myeloid leukemia

Acute Myeloid Leukaemia (AML) is a haematological malignancy showing a hypervariable landscape of clinical outcomes and phenotypic differences, explainable by heterogeneity at the cellular and molecular level. Among the most common genomic alterations, CBFB-MYH11 rearrangement and FLT3-ITD gene mutations, have opposite clinical significance and are unfrequently associated. We present here a Molecular Case Report in which these two events co-exist an ultra-aggressive phenotype resulting in death in 4 days from hospital admittance. Somatic and germline Whole Exome Sequencing analysis was performed to uncover other putative driver mutations, de-novo genomic structural events or germline clusters increasing cancer insurgence. Only three mutations in LTK, BCAS2 and LGAS9 were found, unlikely causative of the exhibited phenotype, prompting to additional investigation of the rare CBFB-MYH11/ FLT3-ITD scenario.