Acute Myeloid Leukemia in Children Less Than Two Years Old: Clinical, Cytologic and Cytogenetic Correlations Comparison with other age categories. A clinical survey of 39 cases

Thirty-nine children under two years of age with newly diagnosed Acute Myeloid Leukemia (AML) were consecutively admitted to the Hôpital Saint-Louis (Paris) over a ten-year period (1978-1987). Nineteen were under one year of age at diagnosis and 3 had congenital leukemia. Comparison of FAB sub-classes among the different age categories showed that AML with a monocytic component (M4 and M5) (44%), and AML with megakaryocytic elements (M7) (21%), were much more frequent in children before the age of two years. This comparison was made on a series of 1409 AML and 859 ALL diagnosed in the same hospital during a twelve years period of time. During this period of observation, the compared incidence of ALL and AML showed 50% for each category for children under 2 years, 73% ALL versus 27% AML for children under 15 years, and 18% ALL versus 82% AML for adults. Of the 29 cases subjected to cytogenetic study, 62% had clonal chromosomal abnormalities, the most frequent being a translocation involving the long arm of chromosome 11. With a 72 months median follow-up for patients who are still alive, the 6-year actuarial survival was 23%, while the event free interval for Complete Remission (CR) patients was 35%. For the M4-M5 subgroup, these results were 37% and 50% respectively with a plateau reached at 27 months. M4-M5 FAB types represented the most common leukemia at this age, and these usually correlated with translocation of the long arm of chromosome 11. We obtained an unexpectedly high rate of survival, with acceptable sequellae, for children treated with intensive chemotherapy.