Comparison of total body irradiation versus non-total body irradiation containing regimens for de novo acute myeloid leukemia in children

Abstract

With limited data comparing hematopoietic cell transplant outcomes between myeloablative total body irradiation (TBI) containing and non-TBI regimens in children with de novo acute myeloid leukemia, the aim of this study was to compare transplant-outcomes between these regimens. Cox regression models were used to compare transplant-outcomes after TBI and non-TBI regimens in 624 children transplanted between 2008 and 2016. Thirty two percent (n=199) received TBI regimens whereas 68% (n=425) received non-TBI regimens. Five-year non-relapse mortality was higher with TBI regimens (22% vs. 11%, p<0.0001) but relapse was lower (23% vs. 37%, p<0.0001) compared to non-TBI regimens. Consequently, overall (62% vs. 60%, p=1.00) and leukemia-free survival (55% vs. 52%, p=0.42) did not differ between treatment groups. Grade II-IV acute GVHD was higher with TBI regimens (56% vs. 27%, p<0.0001) but not chronic GVHD. The 3-year incidence of gonadal or growth hormone deficiency was higher with TBI regimens (24% vs. 8%, p<0.001) but there were no differences in late pulmonary, cardiac or renal impairment. In the absence of a survival advantage, the choice of TBI or non-TBI regimen merits careful consideration with the data favoring non-TBI regimens to limit the burden of morbidity associated with endocrine dysfunction.

Figure 1.

Non-relapse mortality and relapse. (A) Cumulative incidence of non-relapse mortality with total body irradiation (TBI)-containing and non-TBI regimens, (B) cumulative incidence of relapse with TBI-containing and non-TBI regimens.

Figure 2.

Leukemia-free survival and overall survival. (A) Probability of overall survival with total body irradiation (TBI)-containing and non-TBI regimens, (B) probability of leukemia-free survival with TBI-containing and non-TBI regimens.