ESPE Yearbook of Paediatric Endocrinology

Brief Summary: This retrospective, single-center study from Kobe Children’s Hospital, Japan, analyzed height SDS (main outcome) and risk of short stature (height <-2 SDS, secondary outcome) in 89 children with malignant diseases who underwent initial allogenic hematopoietic stem cell transplantation (HSCT) with different conditioning intensities. More intensive conditioning conferred a substantially higher risk of short stature at 3 years after HSCT.

58 patients received myeloablative conditioning (MAC, comprising TBI at >8 Gy and busulfan >8 mg/kg). 31 patients received reduced intensity conditioning (RIC). Median age at HSCT was lower in the RIC group (2.0 years) than MAC (9.3 years). Acute lymphoblastic leukemia (ALL) was the most common primary disease in the MAC group (59%), but not in the RIC group (16%). MAC was associated with a marked increase in the risk of short stature at 3 years after HSCT (adjusted OR: 5.6). Patients with and without ALL were compared, because corticosteroids suppress GH secretion and they still represent key drugs for ALL treatment. No difference was found between the ALL and non-ALL groups in height SDS at HSCT, and 1, 2, 3, 4, and 5?years after HSCT. No correlation was found between age at HSCT or total dose of TBI and height SDS at different time points.

RIC regimens, a well-recognized approach for allogenic HSCT for malignant and non-malignant diseases, aim to decrease short- and long-term complications induced by MAC. In this interesting study, RIC regimen reduced the risk of short stature after HSCT. Height SDS at 2 and 3 years after HSCT was lower in the MAC group, but significant differences in the height SDS at 4 and 5 years after HSCT between the two groups were not observed, probably due to the small number of patients at those times.

There are some limitations: the design is retrospective and selection bias is plausible because physicians may have avoided TBI in younger children. Moreover, the primary diseases were different in the MAC and RIC groups, and patients may have received treatments with a diffferent impact on height before HSCT. Finally, the sample size and the proportion of patients reaching final height during follow up were small, with no data available on bone age.