Hypofractionated radiotherapy in children with diffuse intrinsic pontine glioma

Background Overall survival (OS) of patients with diffuse intrinsic pontine glioma (DIPG) is poor, with radiation therapy (RT) the only intervention that transiently delays tumor progression. Hypofractionated RT and re-irradiation at first progression have gained popularity in improving the quality of life of such patients. Methods We performed a retrospective review of children with DIPG treated at Kanagawa Children's Medical Center from 2000 to 2018. Results A total of 24 cases were reviewed. Median age at diagnosis was 6.3 years (1.6-14.0). Twenty patients received RT only once. Thirteen patients received conventionally fractionated RT, and seven patients received hypofractionated RT as up-front RT. Severe toxicities were not observed in patients who received hypofractionated RT. Median OS and time to progression were similar between conventionally fractionated and hypofractionated RT groups.(9.7 [95% confidence interval(CI): 7.1-11.2] versus 11.0[95% CI: 5.2-13.6] months, P = 0.60; 4.2[95% CI: 1.8-8.3] versus 7.1 [95% CI:4.5-8.7] months, P = 0.38). Four patients received re-irradiation at first progression and all patients showed transient neurological improvement and survival more than a year after diagnosis. A 4-year-old boy was re-irradiated 5-and-a-half months after the first re-irradiation; following transient neurological improvement. He survived a further 5 months. Conclusion Hypofractionated RT for children with newly diagnosed DIPG is well tolerated and feasible from the viewpoint of reducing a patient's burden of treatment. Re-irradiation at first progression is suggested to be beneficial.