HG-57RE-IRRADIATION IN PATIENTS WITH DIFFUSE INTRINSIC PONTINE GLIOMAS, AN UPDATE ON THE CANADIAN EXPERIENCE

Abstract

OBJECTIVE: More than 90% of the children diagnosed with DIPG will succumb within two-years of diagnosis. Clinical-trials have failed to demonstrate a survival benefit of adjuvant chemotherapy. Radiotherapy is the only effective treatment thus far but of limited duration. The aim of this study is to determine the safety and efficacy of re-irradiation. Method: Weretrospectivelyreviewed demographic,clinicalandradiationdataofallpatients with DIPG treated in Canada with re-irradiation. Results: Since January 2011, 13 patients with progressive DIPG received re-irradiation. Median age at diagnosis was 5 years. Median time from diagnosis to progression was 12 months (range,4-37m). Re-irradiation total dose varied between institutions from 21.6Gy to 36Gy. Re-radiation was given focally in 85% of the patients. Re-irradiation was well tolerated by all children. Four patients had transient tiredness and decrease of appetite during treatment. One patient suffered pontine necrosis with brainstem dysfunction with 30Gy in 10 fractions. All but two showed neurological improvement. With a median follow-up from diagnosis of 19.8 months, all patients died, with a median time from re-irradiation to death of 6 months (range,5-13m). When compared to an historiccohort of 46 patients, median time fromprogression to deathwas 92 days in the non re-irradiated patients, vs. 173 days in the re-irradiated ones (p < 0.05). Conclusion: In this limited experience re-irradiation was safe and feasible in patients with progressive DIPG, providing neurological recovery and a prolonged life span. A prospective Canadian re-irradiation protocol is in progress to evaluate treatment benefit including quality of life. Neuro-Oncology 18:iii48-iii77, 2016.