Outcome of single fraction total body irradiation-conditioned stem cell transplantation in younger children with malignant disease Comparison with a busulphan-cyclophosphamide regimen

The logistic difficulties of using fractionated total body irradiation (TBI) in the youngest children often limit the choice to single fraction TBI (sfTBI) or non-TBI-based regimens. We retrospectively evaluated 44 such children (<7 years) conditioned with either sfTBI (n=26) or busulphan-cyclophosphamide (Bu-Cy) (n=18), transplanted for hematological malignancies between 1988 and 2001. Both neutrophil and platelet engraftment were faster in the sfTBI group with a similar incidence of graft failure (6.8%). Acute GVHD (graft versus host disease) grade 2–4 occurred in 38.4% and 38.8% and chronic GVHD in 20% and 15.4% of the patients in the sfTBI and Bu-Cy groups, respectively. Grade 2–4 GVHD was associated with reduced risk of relapse (p=0.03). This finding was more pronounced in high-risk patients with 2/10 relapses in patients with GVHD grade 2–4, compared with 13/18 relapses among those with GVHD 0–1 (p=0.05). The probability of overall survival was 43.3% in the sfTBI group and 33.3% in the Bu-Cy group (...