A comprehensive multicenter analysis of clinical, molecular, and imaging characteristics and outcomes of H3 K27–altered diffuse midline glioma in adults

OBJECTIVE The objective was to comprehensively investigate the clinical, molecular, and imaging characteristics and outcomes of H3 K27–altered diffuse midline glioma (DMG) in adults. METHODS Retrospective chart and imaging reviews were performed in 111 adult patients with H3 K27–altered DMG from two tertiary institutions. Clinical, molecular, imaging, and survival characteristics were analyzed. Characteristics were compared between adult and 365 pediatric patients from a previous multicenter meta-analysis dataset. Cox analyses were performed to determine predictors of overall survival (OS) in adult patients. RESULTS The median (range) age of adult patients was 40 (18–75) years, and 64 males and 47 females were included. Adults had a higher male proportion (57.7% vs 45.3%, p = 0.023), lower proportion of histological grade 4 (41.4% vs 74.0%, p < 0.001), and different tumor locations (p < 0.001) compared with pediatric patients; adults commonly showed a thalamus location (41.5%) followed by the spinal cord (27.0%), whereas pediatric patients predominantly showed a pons location (64.9%). The OS of adults was longer than that of pediatric patients (30.3 vs 12.0 months, p < 0.001, log-rank test). Older age at diagnosis (HR 0.96, p = 0.001), histologically lower grade (HR 0.25, p = 0.003), and gross-total resection of nonenhancing tumor (HR 0.15, p = 0.003) were independent favorable prognostic factors. CONCLUSIONS Adult patients with H3 K27–altered DMG showed distinct clinical, histological, and imaging characteristics compared to pediatric counterparts, with a significantly better prognosis. The authors’ results suggest that aggressive surgery should be pursued when deemed feasible for better survival outcomes.