UCSF

BackgroundDiffuse intrinsic pontine glioma (DIPG) is a rare, aggressive brain tumor with no known cure. Reirradiation (reRT) at recurrence can prolong survival. The impact of irradiation may be heightened when combined with PD-1 inhibition. We describe our experience using reRT, with or without PD-1 inhibition, in a cohort of patients with recurrent DIPG.MethodsWe performed a retrospective cohort analysis of children who received reRT with or without concomitant PD-1 inhibition for recurrent DIPG at a single institution between 2005 and 2016. We compared progression-free (PFS) and overall survival (OS) between those who received reRT alone or in combination with PD-1 inhibition. We then compared reRT to a cohort of patients who did not receive reRT.ResultsThirty-one patients were included (8—reRT with nivolumab; 4—reRT alone; 19—no reRT). Patients who received reRT had prolonged OS compared to no reRT (22.9 months—reRT with nivolumab; 20.4 months—reRT alone; 8.3 months—no reRT; p < 0.0001). Patients who received reRT with nivolumab vs. reRT only had slightly prolonged OS from diagnosis and from reRT (22.9 vs. 20.4 months for time from diagnosis; 6.8 vs. 6.0 months for time from reRT). All patients receiving reRT with or without nivolumab tolerated the therapy without acute or late toxicity.ConclusionsOur experience demonstrates the tolerability of reRT with concurrent PD-1 inhibition for recurrent DIPG and suggests that combination therapy may offer survival benefit. Future prospective studies are needed to confirm the benefits of this combination therapy.