Is Acute Myeloblastic Leukemia in Children Under 2 Years of Age a Specific Entity? A Report from the FRENCH ELAM02 Study Group

Abstract

The clinical and biological characteristics of children under 2 years (infants) with acute myeloid leukemia (AML) are different from those of older children. We aimed to describe the specific characteristics of this population and the potential factors that influence the prognosis. We analyzed data concerning 438 children with newly-diagnosed AML treated in the ELAM02 protocol between March 2005 and December 2011, of which 103 were under 2 years old at diagnosis. The evaluation criteria were overall survival (OS) and event-free survival (EFS) of infants vs older children. The clinical and biological features were secondary criteria. Infants presented more frequent extra-medullary presentation than older children. They had a significantly higher proportion of skin lesions and central nervous system involvement (15% vs 3%, p < 0.0001 and 26% vs 12%, p = 0.0005, respectively). The global incidence of KMT2A rearrangements was nearly 55% for infants vs 11% for older children (p < 0.0001). Median 5-year OS was 70.4% for infants vs 71.4% for older children (p = 0.83). Five-year EFS was 67% for infants vs 58% for older children (p = 0.27). Infants with AML represent a cohort of patients with specific clinical and biological features. These remarkable differences had no significant impact on their outcome in the ELAM02 protocol.

Infant Acute Myeloid Leukemia: A Unique Clinical and Biological Entity

“…In the infant group, rearrangement of KMT2A (formerly MLL) is the most common cytogenetic alteration, representing more than 50% of the cases while core binding factor (CBF) rearrangements are rare (<5%) [1] (Table 1). Table 1.…”

“…Table 1. Distribution of cytogenetic abnormalities in infants <2 years old acute myeloid leukemia (AML) [1]. CBF, core binding factor.…”

“…Infant acute myeloid leukemia (AML) has been conventionally defined as AML in patients aged <1 year [ 1 , 2 , 8 ]. If infant specific features can be seen up to 3 years, they are more prominent up to 2 years of age and many groups agree to define the infant group by children less than 2 years of age [ 1 , 9 ]. The characteristics of infant AML specificities may be related to developmental processes and fetal hematopoiesis features that are still expressed beyond the age of one.…”

“…Infant acute myeloid leukemia (AML) is a rare disease, historically defined by AML occurring under 1 year of age. This definition has been extended to AML in children up to 2 years of age as patients aged from 1 to 2 years old demonstrate similar clinical and biological pattern of disease [ 1 ].…”

“…Rare and atypical clinical presentations in babies have been described for a long time. Similarly, pathologists have reported distinctive distribution of FAB subgroups with predominance of acute megakaryoblastic leukemia (AMKL) and acute monocytic leukemia [ 1 ]. AMKL is highly associated with this subgroup and is rare in other age groups.…”