Three and Four Courses of Radiation for Children with Recurrent Diffuse Intrinsic Pontine Glioma

Purpose: Re-irradiation (RT2) for children with diffuse intrinsic pontine glioma (DIPG) is increasingly used upon recurrence; however, limited data are available for evaluating additional courses of radiotherapy (RT) for DIPG. The purpose of this case series was to report our institutional experience in treating patients with recurrent DIPG with three (RT3) or four (RT4) courses of RT. Material and Methods: A retrospective study of all children with DIPG treated with RT3 or RT4 at a single institution was performed. Medical records were reviewed, and composite dosimetry across all delivered courses of RT was reconstructed. All patients received conventionally fractionated photon RT at 1.8-2 Gy per day, with RT3 or RT4 dose prescriptions ranging 18-21.6 Gy in 10-12 fractions to the brainstem. Results: Five patients were identified; four received three courses of RT while one received four to the brainstem. Median survival from the last course of radiation to death was 4 months; median survival from the first course of RT was 26 months. The median cumulative brainstem D0.03cc for all courses of radiation was 104 Gy (interquartile range: 102-112 Gy). The median time from RT2 to RT3 was 8 months, with partial neurologic recovery (80%) or stable symptoms (20%) after RT3. Radiological appearance of tumor or brainstem necrosis was reported in two patients after RT3 (40%). Conclusions: A third course of RT may be carefully considered as a treatment option for selected children with recurrent DIPG to provide palliation of neurologic symptoms.