Evaluating the Feasibility and Safety of Daily Inter-facility Travel for Proton Beam Therapy During Chemotherapy-Induced Myelosuppression in Children With Cancer

INTRODUCTION: Proton beam therapy (PBT) is widely used in pediatric oncology to reduce radiation exposure to normal tissues and mitigate late adverse effects. In Japan, the limited availability of centers that can provide pediatric PBT with sedation and/or concurrent chemotherapy often necessitates inter-facility travel. However, the safety of daily inter-facility travel for PBT during chemotherapy-induced myelosuppression has not been well evaluated. We assessed the feasibility and safety of this model in Nagano Prefecture. METHODS: We conducted a retrospective cohort study using data from three hospitals in Nagano Prefecture (Nagano Children's Hospital, Shinshu University Hospital, and Aizawa Hospital) from June 2011 to August 2021. Patients who underwent PBT at a proton center with daily inter-facility travel during chemotherapy-induced myelosuppression were compared with patients who received conventional X-ray therapy (XRT) without transfer. Myelosuppression was defined as an absolute neutrophil count