N. Van Roy PhD

Retrospective analysis of the incidence and characteristics of paediatric myelodysplastic syndrome and juvenile myelomonocytic leukaemia in Belgium

SUMMARY

Childhood myelodysplastic syndrome (MDS) and juvenile myelomonocytic leukaemia (JMML) are very rare clonal stem cell disorders of early childhood. Paediatric MDS can be further subdivided in refractory cytopenia of childhood (RCC) and high grade MDS, in case of excess blasts. Given their rarity, little is known about the epidemiology of these diseases in Belgium. The aim of this study is to investigate the incidence, characteristics, treatment and prognosis of paediatric MDS and JMML in Belgium. Prospectively collected data of 56 Belgian patients with MDS and JMML were enrolled in the study, of which 41 (73%) with MDS, eleven with JMML (20%) and four (7%) with Noonan syndrome associated myeloproliferative disorder. The incidence rates of MDS and JMML in Belgium were 1.5 and 0.4 per million children per year respectively, with a median age of diagnosis of 9.3 years for RCC, 9.5 years for high grade MDS and 2.6 years for JMML. Monosomy 7 was the most common cytogenetic abnormality and could particularly be found in high grade MDS (33%) and JMML (45%). RCC treatment consisted of immunosuppressive therapy (IST) and haematopoietic stem cell transplantation (HSCT), but in high grade MDS and JMML only HSCT was a valid treatment option. Overall survival was significantly lower in high grade MDS (45.0%) compared to JMML (79.5%) and RCC (80.6%) (log-rank p-value = 0.038), whereas event-free survival (EFS) was comparably low in high grade MDS and JMML (46.7% and 58.4% respectively) due to a high cumulative incidence of relapse (CIR) of 33% and 29.9%, respectively. Outcome was best for RCC patients with highest EFS (76.3%; 57.1% if IST failure was considered as event) and lowest CIR (9.3%). This study highlights that paediatric MDS and JMML are very rare disorders with associated morbidity and mortality, especially in high grade MDS and JMML. Considering the high relapse risk in high grade MDS and JMML, new therapeutic options are required.

(BELG J HEMATOL 2020;11(6):233-9)

PP01 Exploring the long non-coding RNA landscape in Juvenile Myelomonocytic Leukemia

P09 A case of chronic eosinophilic leukemia with secondary transformation to acute myeloid leukemia

P45 Donor cell derived deletion 7q occurring after allogeneic stem cell transplantation: a case report

A case report of a paediatric Early T-cell Precursor Lymphoblastic Leukaemia

SUMMARY

We describe a case of a four-year-old boy diagnosed with an Early T-cell Precursor Lymphoblastic Leukaemia. This type of leukaemia is recognised as a high-risk subgroup characterised by very early arrest in T-cell differentiation. Early T-cell Precursor Lymphoblastic Leukaemia cases have characteristic gene expression profiles, increased genomic instability and a distinct immature immunophenotype (CD1a–, CD8–, CD5^+dim and positivity for at least one marker of stem cell or myeloid lineage). This type of leukaemia is associated with poor prognosis and a poor response to intensive chemotherapy, though this finding is still debated. Our patient displayed an inferior response to induction therapy. The main purpose of this report is to make Belgian physicians aware of this entity and its controversial prognostic significance.

(BELG J HEMATOL 2017;8(2):75–9)

P35 In-house developed 15-gene sequencing panel for acute myeloid leukemia and myelodysplasia allows robust detection of genetic defects including FLT3-ITD and CEBPA mutations

P2.07 MPN with JAK2 V617F mutation and identical del20q11.2 in three first-degree relatives without identified germline defect