Volumetric de-escalation and improved acute toxicity with proton craniospinal irradiation using a vertebral body-sparing technique.

VBSpCSI in children is a volumetric de-escalation from traditional volumes, which irradiate the entire VB to full or intermediate doses. In our study, VBSpCSI was associated with lower rates of acute GI and hematologic toxicities. Long-term growth outcomes and disease control outcomes are needed for this technique.