Clinical features and outcomes of infant acute lymphoblastic leukemia from a single center in China

Abstract Background Although acute lymphoblastic leukemia (ALL) in infants is rare, the outcomes of patients with this disease are poor. We investigated the clinical features and outcomes of infant patients ( Methods We retrospectively reviewed the clinical data of 21 infants diagnosed with ALL at our department between January 1, 2014 and September 30, 2019. We analyzed their clinical features, overall survival (OS), and event-free survival (EFS) rates. Results The patients’ median age was 5 months old (24 days–11 months old). At initial diagnosis, the median white blood cell count (WBC) was 46.14 × 109/L (6.46–513 × 109/L). Of 18 patients who underwent fusion gene detection, 72.2% (n = 13) had KMT2A rearrangement. Of 12 patients who received chemotherapy, 83.3% (n = 10) achieved complete remission after induction therapy. The expected 2-year OS rate was 58.3 ± 14.2%, while the EFS rate was 41.7 ± 14.2%. The 2-year EFS was 25 ± 15.3% and 75.0 ± 21.7% in patients with KMT2A rearrangement and KMT2A germline, respectively. Of 12 patients, 5 (41.7%) experienced relapse. Three patients underwent hematopoietic stem cell transplantation; of these, one survived. Univariate analysis identified WBC ≥100 × 109/L at initial diagnosis as a risk factor for poor EFS. Conclusions Overall, the outcome for cases of infant ALL with KMT2A germline is favorable; this type of leukemia has similar outcomes when treated with the infant-specific or standard childhood ALL regimens. Thus, the protocol we used may be a suboptimal treatment for infant ALL with KMT2A germline. Moreover, hematopoietic stem cell transplantation seems to improve the outcome of patients with KMT2A germline and post-treatment high minimal residual disease.