Cohort Analysis:
A total of 347 newly-diagnosed children with ALL identified from
pediatric oncology research database based on the study-defined
inclusion and exclusion criteria. The study cohort comprised of
thirty-one children who either relapsed or were resistant to first-line
therapy and received salvage therapy , statistical analysis analysis was
performed on these patients and their clinical characteristics at
diagnosis and at relapse are shown in Table 1.
Three patients experienced induction failures (IF) and 28 relapsed,
total of 31 patients with a cohort relapse incidence of 9% (31/347)
identified. Overall, 4/28 (14%) relapses occurred on first-line therapy
and 24 /28(86%) after completion of therapy. In the patients who
relapsed, the CR1 duration ranged from 2.3 to 99 months with a mean of
26 months and median of 2 months. while with 15 (48%) patients relapsed
≤ 18 months, while seven (23%) relapsed during 18 to 36 months and nine
(29%) patients relapsed > 36 months of IF or CR1.Eighteen
patients (62%) had isolated Bone Marrow (BM) relapse, six (20%)
patients experienced isolated Extra-medullary relapse (four patients
experienced isolated CNS relapse and one-patient experienced isolated
testicular relapse) and the remaining five (17%) patients experienced
BM with other sites(BM+CNS in four patients and BM + Testis in one
patient). Risk stratification of patients at relapse was completed as LR
in two (6%) patients, IR in seven (23%) patients and majority of the
patients twenty-two (71%) patients were stratified as HR prior to
salvage therapy was administered. Seventeen patients (55%) patients
first-salvage chemotherapy, while fourteen (45%) received
second-salvage therapy and Thirteen (42%) patients proceeded to receive
Hematopoietic Stem Cell Transplantation (HSCT). The above-mentioned
clinical features of relapsed patient are shown in Table 2.