Reirradiation for diffuse intrinsic pontine glioma in an upper middle-income country: does full dose improve outcomes?

PURPOSE: Reirradiation (reRT) during diffuse intrinsic pontine glioma (DIPG) progression has emerged as a potential treatment strategy for prolonging survival. METHODS: This retrospective, single-center observational study was conducted on children diagnosed with DIPG between 2010 and 2025, and data from 58 were collected. Doses for reRT were as follows: 50-54 Gy (1.8-2.0 Gy daily/fractions) or 39 Gy (3 Gy daily/fractions). Overall survival (OS) was defined as the time from diagnosis to the date of death and reRT OS, reirradiation starting to death. The Kaplan-Meier method and log-rank test were used for survival analysis. RESULTS: The median age was 7.1 years (range 2.9-16.2 years). Twenty-six patients underwent a biopsy. The H3K27M mutation was the most prevalent in our study, followed by TP53 altered gene. Twenty-two patients underwent reRT at progression. The median time from initial treatment to reRT was 9.9 months (range 6.7 to 20.5 months). Seven of the 22 patients received reRT at a dose of 39 Gy while 14 at doses of 50-54 Gy. The median OS from reRT to death was 5.8 months (range, 0.9-18.3 months). Patients who received reRT had a longer OS compared to those who did not (median OS of 17.9 versus 9.8 months; p = 0.005). Longer time for progression (> 9 months) and dose of reRT > 50 Gy were statistically significantly correlated with better OS. Reirradiation was generally well-tolerated by all patients. CONCLUSIONS: This study offers molecular insights into this tumor type and presents a therapeutic option with higher nominal doses reRT within a palliative context to prolong survival of these patients.