Infection Mortality in Acute Promyelocytic Leukemia in Children

Abstract Background Acute promyelocytic leukemia (APL) is a rare entity in children. The percentage of APL patients is 5-7% of all pediatric acute myeloid leukemia cases; a higher frequency (about 20%) is reported in children of Latino/Hispanic ancestry. The introduction of trans retinoic acid has been crucial for both antileukemic efficacy in APL and for prevention of early deaths. Furthermore, the use of arsenic trioxide (ATO) demonstrated to be highly effective in achieving high cure rates with reduced toxicity. However, there is a paucity of data concerning infection related deaths in APL. The objective was to describe the percentage of infection-related-deaths in APL in children; to describe the event free survival (EFS) and describe other main complications observed. Methods We identified 30 patients, as part of the Hospital Alejandro Posadas registry from a single center. We conducted a retrospective observational descriptive analysis. The patients were treated with the GIMEMA-AIDA 2000 protocol (n=23, 76.7%) and 1-LPA pediatrico-18-GALTA/CLEHOP (n=6, 20%). One patient died before treatment was given. The patients were diagnosed between 2000 to 2022. We used frequencies for descriptive variables, Chi2 /Fisher test for categorical data and time to event techniques for survival analysis. Any cause of mortality was extracted and analyzed. Results There were 66.7% of males; and median age was 12-year (IQR 8-15). PML-Rar alfa was positive (cytogenetics) in 23 (76.7%); Negative 6 (20%) and failed in 1 patient (3.3%). 100% had positive molecular biology for PML-rarAlfa transcript. Median white cells were 3.35x 109 /l (IQR 1.675-13.25). The patients were classified as high-risk (n=10, 33.3%) and standard risk (n=20, 66.7%). Four patients showed molecular relapse, 2 had CNS and one bone marrow involvement. Three patients died (10%), 2 due to endocranial hemorrhage, 1 as a consequence of complications of a hematological relapse. No patient died due to microbiologically documented infection or febrile neutropenia. With a mean estimated survival time (median not achieved) in years of 17.7 years, (CI 95% 14.6-20.7) the event free survival was 79% (SE 0.75), with 6 events. Cumulative competitive incidence of relapse 14% (SE 0.65). Conclusion In patients with APL, we could not find infections as cause of death. The overall results of APL management were very promising. Figure 1. Event Free Survival Acute Promyelocytic Leukemia.