Long-term complications after total body irradiation in children younger than 4 years transplanted for acute...

Area of Science:

• Pediatric Oncology
• Hematopoietic Stem Cell Transplantation
• Radiation Oncology

Background:

• Total body irradiation (TBI)-based conditioning is standard for high-risk pediatric acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (HSCT).
• Its use in children under 4 years is limited due to concerns about long-term toxicity.

Purpose of the Study:

• To compare long-term physical, educational, and quality-of-life outcomes in pediatric ALL patients who received TBI-based HSCT at 2 to <4 years versus those transplanted at ≥4 years.
• To assess the long-term toxicity associated with TBI-based HSCT in younger children.

Main Methods:

• A cohort study of pediatric ALL patients from the French LEA follow-up program.
• Comparison of outcomes between a younger group (2 to <4 years, n=37) and a matched older group (≥4 years, n=105).
• Analysis of complications, educational attainment, and quality of life after a mean follow-up of 15.6 years.

Main Results:

• Overall complication rates were similar between the younger and older groups (3.3 vs 3.2).
• Pulmonary dysfunction was more frequent in the older group (43% vs 19%, p=0.01).
• Age group was not associated with an increased risk of greater complication burden (HR 1.05). Educational outcomes and quality of life were comparable.

Conclusions:

• TBI-based HSCT in children aged 2 to <4 years does not appear to confer greater long-term toxicity compared to older children.
• These findings support reconsidering the lower age limit for TBI-based HSCT in pediatric ALL.
• Long-term physical, educational, and quality-of-life outcomes are comparable between the age groups.