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ESTRO ACROP and SIOPE recommendations for myeloablative Total Body Irradiation in children
Bianca A W Hoeben1, Montserrat Pazos2, Enrica Seravalli3
1Dept. of Radiation Oncology, University Medical Center Utrecht, The Netherlands; Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands.
Insights
Standardized recommendations for myeloablative Total Body Irradiation (TBI) in children undergoing hematopoietic stem cell transplantation (HSCT) are crucial. These guidelines aim to improve outcomes and reduce late adverse effects in pediatric patients with high-risk leukemia.
Area of Science:
- Pediatric Oncology
- Radiation Oncology
- Hematopoietic Stem Cell Transplantation
Background:
- Myeloablative Total Body Irradiation (TBI) is a key conditioning regimen for allogeneic HSCT, particularly in pediatric high-risk acute lymphoblastic leukemia (ALL).
- Current TBI practices exhibit significant heterogeneity and institutional variability.
- TBI is associated with substantial late adverse effects, necessitating standardization to optimize the benefit-to-toxicity ratio in children.
Purpose of the Study:
- To develop consensus recommendations for myeloablative TBI techniques and toxicity management in pediatric HSCT.
- To provide guidance for standardizing TBI practices across institutions.
- To improve treatment outcomes and reduce long-term toxicities in children undergoing HSCT.
Main Methods:
- A literature search and evaluation of myeloablative TBI techniques and toxicities in pediatric populations were conducted.
- Expert consensus was established through bimonthly virtual meetings by the European Society for Paediatric Oncology (SIOPE) Radiotherapy TBI Working Group and ESTRO experts.
- Evidence levels from retrospective studies (III-IV) were considered.
Main Results:
- Myeloablative TBI is primarily used for high-risk ALL and relapsed hematologic malignancies in children, with caution advised for those younger than 3-4 years due to toxicity risks.
- Recommended TBI dose is 12-14.4 Gy in 1.6-2 Gy fractions b.i.d., with specific dose reductions for organs at risk: lungs (<8 Gy), kidneys (≤10 Gy), and lenses (<12 Gy) at dose rates ≥6 cGy/min.
- Advanced techniques like TomoTherapy, VMAT TBI, and Total Marrow (and/or Lymphoid) Irradiation show promise for improved dose homogeneity and organ sparing and warrant further study.
Conclusions:
- ESTRO ACROP SIOPE have established expert consensus recommendations for myeloablative TBI in pediatric HSCT.
- These recommendations cover both conventional and advanced conformal TBI techniques.
- The guidelines aim to standardize TBI practices and improve the management of toxicities in children undergoing HSCT.
Background And Purpose:
Myeloablative Total Body Irradiation (TBI) is an important modality in conditioning for allogeneic hematopoietic stem cell transplantation (HSCT), especially in children with high-risk acute lymphoblastic leukemia (ALL). TBI practices are heterogeneous and institution-specific. Since TBI is associated with multiple late adverse effects, recommendations may help to standardize practices and improve the outcome versus toxicity ratio for children.
Material And Methods:
The European Society for Paediatric Oncology (SIOPE) Radiotherapy TBI Working Group together with ESTRO experts conducted a literature search and evaluation regarding myeloablative TBI techniques and toxicities in children. Findings were discussed in bimonthly virtual meetings and consensus recommendations were established.
Results:
Myeloablative TBI in HSCT conditioning is mostly performed for high-risk ALL patients or patients with recurring hematologic malignancies. TBI is discouraged in children <3-4 years old because of increased toxicity risk. Publications regarding TBI are mostly retrospective studies with level III-IV evidence. Preferential TBI dose in children is 12-14.4 Gy in 1.6-2 Gy fractions b.i.d. Dose reduction should be considered for the lungs to <8 Gy, for the kidneys to ≤10 Gy, and for the lenses to <12 Gy, for dose rates ≥6 cGy/min. Highly conformal techniques i.e. TomoTherapy and VMAT TBI or Total Marrow (and/or Lymphoid) Irradiation as implemented in several centers, improve dose homogeneity and organ sparing, and should be evaluated in studies.
Conclusions:
These ESTRO ACROP SIOPE recommendations provide expert consensus for conventional and highly conformal myeloablative TBI in children, as well as a supporting literature overview of TBI techniques and toxicities.
