Radiation and subsequent reirradiation outcomes in the treatment of diffuse intrinsic pontine glioma and a systematic review of the reirradiation literature.

PURPOSE: Diffuse intrinsic pontine glioma (DIPG) is a devastating pediatric disease, with a median survival of <1 year. Here, we review our institution's DIPG experience over an 8-year interval and perform a systematic review of the literature, specifically evaluating reports of reirradiation (reRT) for DIPG. METHODS AND MATERIALS: We retrospectively reviewed the medical records of 26 patients who underwent definitive intensity modulated radiation therapy (IMRT) for DIPG at a single institution between 2007 and 2015. Three of these patients underwent reRT for progressive disease. Clinical endpoints, including progression-free survival and overall survival (OS), were assessed. We then performed a thorough PubMed search of the literature discussing reRT for patients with DIPG. RESULTS: Twenty-four of the 26 patients (92%) completed the initial course of radiation (54 Gy in 1.8-Gy fractions using IMRT). Median age at diagnosis was 6.0 years (range, 2.0-26.5). With respect to systemic therapy, 1 (4.2%) received no systemic therapy, 1 (4.2%) received concurrent systemic therapy alone, 4 (16.7%) received adjuvant therapy alone, and 18 (75%) received a combination of concurrent and adjuvant therapy. Median follow-up time was 11 months from the date of initial diagnosis. Median OS for the cohort was 12 months, with a 1-year OS of 51%. The 3 patients who underwent reRT received 20 Gy in 10 daily fractions using IMRT alone with no treatment toxicity noted. CONCLUSIONS: Radiation therapy is essential in the definitive management of DIPG. With advances in treatment techniques, it is feasible to reirradiate select patients with progressive disease; however, further research is warranted to optimize dose, delivery, and patient selection in the recurrent/progressive setting. In the future, it may be reasonable to propose more focal delivery of reRT (ie, hypofractionated radiation) in select patients with the goal of reducing treatment time and providing effective palliation.