Treatment of Childhood Acute Myeloid Leukemia in Bulgaria.

BACKGROUND: During the last four decades the prognosis of childhood acute myeloid leukemia (AML) has been substantially improved due to an increase in complete remission (CR) rates, event-free survival (EFS) and reduced early mortality. The relapsed AML still remains a therapeutic challenge. AIM: To report the AML treatment results of the Bulgarian pediatric oncohematological centers. MATERIALS AND METHODS: Retrospective analysis of the treatment results of children and adolescents (age from 0 to 20 years) with primary AML. Unified AML BFM- backbone type treatment protocol is used. RESULTS: This study included 97 newly diagnosed patients (44 girls and 53 boys) with AML in Bulgaria between 2003 and 2016. The median age at diagnosis was 10.2 years. The most frequent FAB-morphologic subtype was M2 followed by M4. First complete remission (CR1) was achieved in 83 patients (85.6%). The 13-year EFS was 49%, while the overall survival (OS) was 54.6%. Twenty seven (27.8%) patients relapsed, with only 5 of them being still alive towards the end of the study period. CONCLUSION: The EFS and OS for the children with AML in Bulgaria are comparable with those reported by other European groups. The prognosis of relapsed AML remains still unfavorable for the past 13 years.

Simultaneous occurrence of ETV6-RUNX1 and BCR-ABL1 (e1a2) transcripts in a child with B-cell acute lymphoblastic leukemia.

We report on a rare case of a 3-year-old boy with B-cell acute lymphoblastic leukemia (B-ALL), which was characterized simultaneously with two different fusion transcripts: ETV6-RUNX1 and BCR-ABL1 (e1a2). The patient presented with fever, diarrhea, normal white blood cell counts of 5.9×10(9)/L without circulating abnormal cells, anemia, and thrombocytopenia, as well as an enlarged liver without splenomegaly. The bone marrow was markedly hypercellular with a total infiltration of agranular lymphoid blast cells with a B-II (pre-B) lymphoblastic phenotype: cyCD79α(+), CD19(+), sCD22(+), CD10(+), CD20(-), CD34(+), and sIgM(-), with dim aberrant co-expression of the myeloid-associated markers CD13(+) and CD33(+). Conventional cytogenetic analysis was unsuccessful; however, molecular analysis revealed the BCR-ABL1 (p190) and ETV6-RUNX1 transcripts. A diagnosis of BCR-ABL1 (p190)-positive and ETV6-RUNX1-positive B-ALL was made, and treatment was initiated according to the AIEOP-BFM-ALL2000 protocol. A complete remission was achieved after the first induction course of chemotherapy. Twelve months after the diagnosis, the child is alive with levels of residual disease of <0.05% estimated both by 8-color flow cytometry and real-time quantitative reverse transcription polymerase chain reaction.