Demographics and clinical characteristics
We examined data on 307 pediatric AML patients between 2005 and 2015 and
81 patients (26.38%) with hyperleukocytosis. According to the WBC
count,
the baseline demographic and clinical characteristics of AML patients
with and without hyperleukocytosis compared in
Table
1.
The
proportion of males in the two groups was 55.31% and 61.73,
respectively. Hyperleukocytosis at onset
was
high
in patients with the M5 subtype
(n=41,
50.62%) in the FAB classification,
whereas
without
hyperleukocytosis was high in patients with FAB M2 subtype (n=126,
55.75%). The proportion of intermediate cytogenetics and
FMS-like
tyrosine kinase 3-internal tandem duplication (FLT3-ITD)
was
higher
in
patients with hyperleukocytosis than without hyperleukocytosis
(54.32%
vs. 32.30%,
P<0.001;
19.75% vs. 3.98%, P <0.001).
The
proportion of favorable cytogenetics
and
core binding factor acute myeloid leukemia (CBF-AML) was lower in
patients with hyperleukocytosis than without hyperleukocytosis (18.52%
vs. 44.69%, P<0.001; 22.22% vs. 48.23%,P <0.001) (Table 1). The baseline
demographic
and clinical characteristics of hyperleukocytosis subgroups compared in
Table 1S.
Impact
of hyperleukocytosis on treatment response
Overall
mortality was significantly higher in patients with hyperleukocytosis
than in patients without hyperleukocytosis (50.62% vs. 35.84%,P =.020), while the CR rate after induction was similar between
the two
groups
(75.31%
vs.
76.99%,P =.759) (Table 2). Table 2S illustrates that the CR rate was
significantly higher in
favorable/intermediate cytogenetics
in
the
WBC count 50-100×109/L subgroup than the WBC count
≥100×109/L subgroup (92.31% vs. 63.64%,P =.013), and yet CR rate was no significant difference between
the two subgroups in other circumstances. To our surprise,
there
was no significant difference in mortality rate between the two
subgroups regardless of sex, age,
cytogenetics or specific molecular
alterations.