Abstract
PURPOSE: This study aims to assess oncological outcomes in children and young adults with diffuse infiltrative pontine glioma (DIPG) who have progressed after initial radiotherapy (RT), with an emphasis on the role of re-irradiation. METHODS: Data from 33 patients aged 25 years or younger with progressive disease after initial RT were retrospectively analyzed. RESULTS: The median age at diagnosis was 8 years (range 4-24 years), and the median initial RT dose was 54 Gy (range 39-54 Gy). The median time between initial RT and progression was 8 months (range 3-40 months). In addition to systemic therapy, 15 patients (46%) received re-irradiation due to progression, with a median dose of 23.4 Gy (range 19.8-36 Gy), while 18 patients (54%) were treated with systemic therapy alone. In patients who received re-irradiation after progression, the 1‑year post-progression overall survival (OS) was significantly higher compared to those treated with systemic therapy alone (27% vs. 0%, p = 0.01). Among the 15 re-irradiated patients, 9 out of 12 with available data (75%) showed improvement in neurological symptoms following re-irradiation. No patient exhibited acute or late RT-related ≥ grade 3 toxicity. CONCLUSION: Palliative re-irradiation in children and young adults with progressive DIPG after initial RT provides an approximately 3‑month OS benefit and clinical improvement without significant toxicity and should be considered as a standard-of-care approach.