Single institution experience in re-irradiation of biopsy-proven diffuse intrinsic pontine gliomas.

Objectives: Diffuse intrinsic pontine glioma (DIPG) is the leading cause of death from CNS tumors in children. Multiple clinical trials have failed to show any benefit from systemic therapy in DIPG, and radiation therapy (RT) alone remains the standard of care. Re-irradiation (rRT) for symptomatic relief is an option at disease progression. However, published data on treatment details and outcomes are limited. The objective of this study was to review and report our institutional experience with re-irradiation of patients with biopsy-proven DIPG.

Methods: We identified a cohort of pediatric patients with biopsy-proven DIPG with clinical disease progression after initial radiotherapy who received a second course of radiotherapy at our institution. We reviewed patient and treatment characteristics and outcomes.

Results: Between January 2014 and July 2018, we identified five patients with progressive DIPG who received re-irradiation. Re-irradiation was well tolerated with no serious adverse events reported and all patients experiencing stable to improved neurologic function during treatment. Median survival from completion of re-irradiation was 116 days (range 62 to 159 days). Median overall survival from time of diagnosis was 16.3 months (range 13.0 to 18.0 months), which is longer than the historical average of less than 12 months. In patients with available postmortem neuropathology, common findings were Wallerian degeneration and necrosis.

Conclusions: In our experience, re-irradiation is safe and feasible for patients with DIPG with symptomatic disease progression following initial radiotherapy treatment.