CLINICAL FEATURES AND RESULTS OF THERAPY IN INFANTS AND CHILDREN AGED 1 TO 3 YEARS OLD WITH ACUTE MYELOID LEUKEMIA

Infants of the first year of life represent a unique group of patients with acute myeloid leukemia (AML). Materials and methods of the research: the characteristics of 492 patients with newly diagnosed AML aged 10 DoL-18 y/o who received intensive chemotherapy according to the AML-MM-2006 and AML-MRD-2018 guidelines in Apr. 2007-Apr. 2021 were analyzed. The analysis was carried out separately for infants (<1 y/o, 58/12%), young children (1-3 y/o, 99/20%) and children aged 3-18 y/o (335/68%). Results: the infant group was characterized by a higher incidence of hyperleukocytosis, extramedullary lesions, the predominance of monoblast/monocytic (63%) and megakaryoblast (24%) subvariants and chromosomal aberrations involving the 11q23 locus (KMT2A gene) (53%). “CBF leukemias” were virtually non-existent in infants (0% for t(8;21)(q22;q22.1)/RUNX1::RUNX1T1 and 2% for inv(16)(p13.1q22)/CBF::MYH11) and the rates increased with age. Activating mutations in the FLT3 gene were extremely rare (2% vs. 13.5% in patients >/=3 y/o). Patients of the 1-3 y/o group were similar in morphological and cytogenetic characteristics to the infants’ group but had a smaller tumor mass and higher survival rates. The 5-year overall survival of infants was statistically significantly lower than in older patients, 52% vs. 67% (p<0.001), primarily due to high mortality prior to remission, which in its turn was caused by complications associated with hyperleukocytosis. Conclusions: given the vulnerability of this category of patients, it is reasonable to transfer them to larger medical facilities with extensive experience in the field in order to conduct the remission induction stage (especially cytoreduction) within the intensive care unit.