Prognostic factors and outcomes of infant acute lymphoblastic leukemia (ALL), hypodiploid ALL, and mixed-phenotype acute leukemia (MPAL) in Canada: a report from CYP-C

Abstract

The epidemiology of infant acute lymphoblastic leukemia (ALL), hypodiploid ALL, and mixed-phenotype acute leukemia (MPAL) in Canada is unknown. The main objective was to describe the prevalence, prognostic factors, and outcomes of three rare and high-risk ALL subtypes in Canada. This is a retrospective study using the Cancer in Young People-Canada (CYP-C) database. Event-free survival (EFS) and overall survival (OS) were described by the Kaplan–Meier method and compared using the log-rank test. Among 2626 children aged 0–14 years diagnosed with B-cell acute lymphoblastic leukemia (B-ALL) between 2001 and 2018, 227 (8.6%) patients were identified to be infant ALL (n = 139), hypodiploid ALL (n = 43), or MPAL (n = 45). The 5-year EFS/OS was significantly worse in the infant ALL subgroup compared to that of hypodiploid ALL and MPAL. For the entire cohort, presenting White blood cells (WBCs) ≥50 × 10⁹/L was independently associated with worse EFS/OS.

Keywords:

• Infant acute lymphoblastic leukemia
• hypodiploid
• mixed phenotype acute leukemia

Acknowledgments

The authors gratefully acknowledge the contributions of study participants, participating pediatric oncology centers, members of the Cancer in Young People in Canada (CYP-C) Management and Steering Committees, the Paediatric Oncology Group of Ontario (POGO), and the five POGO Hospital Partners. The CYP-C is fully funded by the Public Health Agency of Canada. We wish to thank all the data managers at the 17 CYP-C sites for their dedicated work in maintaining the CYP-C data quality.

Ethical approval

The study was approved by the Research Ethics Board of CHU Sainte-Justine. The requirement for informed consent and assent was waived given the retrospective nature of this study.

Disclosure statement

THT received consulting fees from Servier and Jazz Pharmaceuticals. The other authors have no conflict of interest to disclose. The analyses and interpretations presented in this work do not necessarily reflect the opinions of the government of Canada.

Data availability statement

Data used in this publication are from the Cancer in Young People in Canada Surveillance Program and are used with the permission of the Public Health Agency of Canada.