In this comparative study, the investigators aim to compare prospective pediatric patients who receive total lymphoid irradiation (TLI) using tomotherapy with age- and disease-matched controls who receive conventional total body irradiation (TBI) as part of conditioning for haploidentical hematopoietic stem cell transplantation (HSCT) for both malignant and non-malignant diseases. The investigators shall evaluate graft failure-free, graft-versus-host disease (GVHD)-free survival, overall survival, frequency of rejection, GVHD, relapse of malignancy, adverse effects and post-transplant immunoreconstitution.
Radiotherapy at a dose of 6Gy divided into 3 equal fractions (2Gy per fraction) to all lymphoid organs (TLI) over 2 days using tomotherapy will be given to participants as part of the conditioning treatment before haploidentical hematopoietic stem cell transplantation (HSCT). Retrospective patients who are age- and disease-matched with the recruited patients and had received radiotherapy to the whole body (TBI) with or without lung shielding at a total dose of 2-12 Gy delivered as 1-6 equal fractions by conventional opposed fields radiotherapy as part of conditioning will be compared for the outcomes.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
23
Total lymphoid irradiation (TLI) 6Gy by tomotherapy as part of conditioning treatment before haploidentical hematopoietic stem cell transplant
Hong Kong Children's Hospital
Hong Kong, Hong Kong
RECRUITINGGraft failure-free, GVHD-free survival
From the date of treatment start until the date of graft failure or GVHD or death from any cause, whichever comes first, assessed up to 1 year
Time frame: up to 1 year
Overall survival
From the date of treatment start until the date of death from any cause, whichever comes first, assessed up to 1 year
Time frame: up to 1 year
Proportion of patients who develop relapse among those with malignant diseases
Relapse is defined as reappearance of biopsy-proven malignant disease after complete remission
Time frame: up to 1 year
Proportion of patients who develop graft failure
Graft failure is defined as donor cells \<5% in whole blood
Time frame: up to 1 year
Proportion of patients who develop acute graft-versus-host disease
Acute graft-versus-host disease is defined by MAGIC criteria
Time frame: up to 1 year
Proportion of patients who develop chronic graft-versus-host disease
Chronic graft-versus-host disease is defined by NIH criteria
Time frame: up to 1 year
Proportion of patients who develop adverse events not mentioned in outcomes 4-6
Adverse events are graded according to Cancer Therapy Evaluation Program Common Terminology Criteria for Adverse Events version 5 (CTCAEv5)
Time frame: up to 1 year
Blood T lymphocyte count at 3 months
Mean T lymphocyte count in blood among evaluable patients
Time frame: at 3 months
Blood T lymphocyte count at 1 year
Mean T lymphocyte count in blood among evaluable patients
Time frame: at 1 year
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