Long-term effects of local radiotherapy on growth and vertebral features
in children with high-risk neuroblastoma
Objectives: To evaluate the effects of local radiotherapy (RT)
on growth, we evaluated the chronological growth profiles and vertebral
features of children with high-risk neuroblastoma. Materials and
Methods: Thirty-eight children who received local photon or proton beam
therapy to the abdomen or retroperitoneum between January 2014 and
September 2019 were included. Simple radiography of the thoracolumbar
spine was performed before and every year after RT. The height and
vertical length of the irradiated vertebral bodies (VBs) compared with
the unirradiated VBs (vertebral body ratio, VBR) were analyzed using the
linear mixed model. Shape feature analysis was performed to compare the
irradiated and unirradiated vertebrae. Results: The follow-up
was a median of 53.5 months (range, 21-81 months) after RT. A decline
in height z-scores was mainly found in the early phase after treatment.
In the linear mixed model with height, the initial height (fixed,
p < .001), sex (time interaction, p = .008),
endocrine dysfunction (time interaction, 0.019), and age at diagnosis
(fixed and time interaction, both p = .002) were significant.
Unlike the trend in height, the change in VBR (ΔVBR) decreased gradually
( p < .001). The ΔVBR in the group that received more
than 30 Gy decreased more than in the group that received smaller doses.
In the shape feature analysis, the irradiated VBs changed to a more
irregular surface that were neither round nor rectangular.
Conclusion: The irradiated VBs in children were gradually
restricted compared to the unirradiated VBs in long-term follow-up, and
higher RT doses were significantly affected. Radiation-induced irregular
features of VBs were observed.