Survival benefit for patients with diffuse intrinsic pontine glioma (DIPG) undergoing re-irradiation at first progression: A matched-cohort analysis on behalf of the SIOP-E-HGG/DIPG working group.
Overall survival of patients with diffuse intrinsic pontine glioma (DIPG) is poor. Current treatment approach consists of upfront irradiation followed by best supportive care. With this strategy, a transient reduction in symptoms can be achieved in most patients but subsequent deterioration and death usually occur within one year. Survival time benefits were shown in smaller pilot studies using re-irradiation at secondary deterioration with acceptable toxicity. The purpose of this study was to analyze benefit and toxicity of re-irradiation at first progression of diffuse intrinsic pontine glioma (DIPG).
This is a multicenter retrospective matched-cohort analysis of children aged 2-16 years with characteristic features of DIPG or biopsy-proven high-grade glioma after first progression. An interval of ≥3 months after upfront radiotherapy was required before re-irradiation. Thirty-one children with DIPG, underwent re-irradiation (dose 19.8–30.0 Gy) alone (N=16) or combined with systemic therapy (N=15). Thirty-nine patients fulfilling the same criteria receiving radiotherapy at diagnosis formed the matched comparative cohort. They were followed by best supportive care (n = 20) or systemic therapy (n = 19) but without re-irradiation at progression. Thirty-nine patients without re-irradiation received best supportive care or systemic therapy only.
Significant benefit in median OS (13.7 versus 10.3 months; P = .04) was observed in favor of patients undergoing re-irradiation. Clinical improvement with re-irradiation was observed in 24/31 (77%) patients. Re-irradiation was well tolerated with no recorded grade 4–5 toxicities. Re-irradiation itself and the interval between upfront radiotherapy and re-irradiation remained independent prognostic factors for OS. A risk score using five categories was useful to predict time of survival at first progression.
This is a retrospective study, and reasons for choosing re-irradiation or another treatment are not revealed. Surprisingly, progression-free survival was not affected by radiotherapy at progression which raises questions about the main outcome of the study.