HG-39: SURVIVAL RATES AND PROGNOSTIC OUTCOMES OF HIGH GRADE BRAIN STEM GLIOMAS IN CHILDHOOD: A SYSTEMATIC REVIEW AND META-ANALYSIS

INTRODUCTION: Diagnosis of a paediatric high grade brain stem glioma is devastating and outcomes remain dismal. This review was undertaken to determine the survival rates and assess potential prognostic factors including selected interventions. METHODS: Systematic review and meta-analysis of mixed study designs (PROSPERO CRD42013006592). Studies included involved paediatric participants with high grade brain stem gliomas diagnosed by MRI or biopsy reporting overall survival rates. Meta-analysis was undertaken using a binomial random effects model. RESULTS: 65 studies (2,254 participants) were included. Meta-analysis showed 1 year overall survival (OS) of 41.3% (95% confidence interval (CI) 38-45%, I-sq 52%, 1940 participants), 2 year OS of 15.8% (95% confidence interval 12-20%, I-sq 72%, 1213 participants) and 3 year OS of 7.3% (95% confidence interval 5.2-10%, I-sq 26%, 584 participants). We were unable to perform meta-analyses of median overall survival results due to lack of variance measures reported. Subgroup meta-analyses of comparing date of study, classification of tumour, use of Temozolomide, non-standard interventions or phase 1/2 vs. other studies demonstrated no difference in survival outcomes. We were unable to perform subgroup meta-analyses of patient age, duration of symptoms, K27M histone mutations and AVCR1 mutations. CONCLUSIONS: Survival outcomes of brain stem gliomas have remained very poor and do not clearly vary according to classification, phase of study or use of different therapeutic interventions. Future studies should harmonise outcome and prognostic variable reporting to enable accurate meta-analysis and better exploration of prognosis.