Purpose: To collate evidence of changes in body composition following treatment of leukaemia in children, teenagers and young adults (CTYA, 0–24 years) with allogeneic haematopoietic stem cell transplant and total body irradiation (HSCT+TBI). 

Methods: Papers were identified by searching Medline and Google Scholar, reference lists/citations and contacting key authors, with no date or language restrictions. Inclusion criteria were as follows: leukaemia, HSCT+TBI, aged ≤ 24 years at HSCT and changes in body composition (total fat, central adiposity, adipose tissue function, muscle mass, muscle function). Quality was assessed using a brief Newcastle–Ottawa scale. 

Results: Of 900 papers, 20 were included: seven controlled, five uncontrolled studies and eight case reports. Study quality appeared good. There was little evidence of differences in total fat/weight for HSCT + TBI groups (compared to healthy controls/population norms/short stature controls). There was some evidence of significantly higher central adiposity and differences in adipose tissue function (compared to leukaemic/non-leukaemic controls). Muscle mass was significantly lower (compared to healthy/obese controls). Muscle function results were inconclusive but suggested impairment. Case reports confirmed a lipodystrophic phenotype. 

Conclusions: Early remodelling of adipose tissue and loss of skeletal muscle are evident following HSCT + TBI for CTYA leukaemia, with extreme phenotype of overt lipodystrophy. There is some evidence for reduced muscle effectiveness.

Implications for Cancer Survivors: Body composition changes in patients after HSCT + TBI are apparent by early adult life and link with the risk of excess cardiometabolic morbidity seen in adult survivors. Interventions to improve muscle and/or adipose function, perhaps utilizing nutritional manipulation and/or targeted activity, should be investigated.