Von Hoff, Katja

Abstract Background Astroblastomas are rare brain tumors predominantly affecting children and young adults, for which molecular subtypes and clinical management remain undefined. Methods We analyzed tumor samples, molecular profiles, and clinical data from 200 patients, classified as “Astroblastoma, MN1-altered” under WHO criteria, using DNA methylation profiling, DNA/RNA profiling/sequencing, and survival analyses. Results DNA methylation analyses identified 3 groups: Group A (n = 143, characterized by MN1::BEND2 fusions, predominantly supratentorial location, with striking female predominance and favorable survival); Group B (n = 37, epigenetically and transcriptionally closely related to Group A, but characterized by EWSR1::BEND2 fusions, with spinal and infratentorial locations and poor prognosis); and Group C (n = 20, epigenetically and transcriptionally distinct, characterized by MN1::CXXC5 fusions, exclusively supratentorially located, with favorable survival). Progression-free and overall survival were significantly shorter in Group B (5-year PFS 14%; 10-year OS 54%) compared to A (5-year PFS 47%; 10-year OS 89%) and C (5-year PFS 75%; 10-year OS 89%). Radiotherapy improved PFS in Group B (hazard ratio 0.25), while no clear benefit was identified for Groups A and C. Conclusions Astroblastoma, MN1-altered, comprises 3 molecularly and clinically distinct groups, characterized by different fusion genes, including those without MN1. These new insights, including the identification of potential predictive biomarkers like 14q/16q loss, provide a framework for the development of risk-stratified therapeutic approaches. Importantly, we identified a molecularly defined high-risk group that benefits from radiation therapy. Our findings redefine Astroblastoma as a molecularly diverse tumor type, propose a refined classification, support the development of risk-adapted therapeutic strategies and provide a rational standard of care.

AbstractPurposeRadiotherapy (RT) is associated with improved survival in atypical teratoid/rhabdoid tumor (ATRT); however, optimal RT delivery is unknown. A meta‐analysis was conducted for disseminated (M+) ATRT receiving focal or craniospinal radiation (CSI).MethodsAfter abstract screening, 25 studies (1995–2020) contained necessary patient, disease, and radiation treatment information (N = 96). All abstract, full text, and data capture were independently double‐reviewed. The corresponding author was contacted for cases of insufficient information. Response to pre‐radiation chemotherapy (N = 57) was categorized as complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD). Univariate and multivariate statistics were performed to investigate survival correlation. Patients with M4 disease were excluded.ResultsThe 2‐ and 4‐year overall survival (OS) was 63.8% and 45.7%, respectively, with a median follow‐up of 2 years (range 0.3–13.5). The median age was 2 years (range 0.2–19.5), and 96% received chemotherapy. On univariate analysis, gross total resection (GTR, p = .0007), pre‐radiation chemotherapy response (p < .001), and high‐dose chemotherapy with stem cell recuse (HDSCT, p = .002) correlated with survival. On multivariate analysis, pre‐radiation chemotherapy response (p = .02) and GTR (p = .012) retained survival significance as compared to a trend for HDSCT (p = .072). Comparisons of focal RT (vs. CSI) and greater than or equal to 5400 cGy primary dose were nonsignificant. Following CR or PR, a statistical trend favored focal radiation (p = .089) over CSI.ConclusionChemotherapy response prior to RT and GTR correlated with improved survival on multivariate analysis for ATRT M+ receiving RT. No benefit was observed for CSI compared to focal RT among all patients and following favorable chemotherapy response, inviting further study of focal RT for ATRT M+.

Abstract Background Pineoblastoma is a rare brain tumor usually diagnosed in children. Given its rarity, no pineoblastoma-specific trials have been conducted. Studies have included pineoblastoma accruing for other embryonal tumors over the past 30 years. These included only occasional children with pineoblastoma, making clinical features difficult to interpret and determinants of outcome difficult to ascertain. Patients and Methods Centrally or independently reviewed series with treatment and survival data from North American and Australian cases were pooled. To investigate associations between variables, Fisher’s exact tests, Wilcoxon-Mann-Whitney tests, and Spearman correlations were used. Kaplan-Meier plots, log-rank tests, and Cox proportional hazards models were used in survival analyses. Results We describe a pooled cohort of 178 pineoblastoma cases from Children’s Oncology Group (n = 82) and institutional series (n = 96) over 30 years. Children &lt;3 years of age have significantly worse survival compared to older children, with 5-year progression-free survival (PFS) and overall survival (OS) estimates of 13.5 ± 5.1% and 16.2 ± 5.3%, respectively, compared with 60.8 ± 5.6% and 67.3 ± 5.0% for ≥3 years old (both P &lt; .0001). Multivariable analysis showed male sex was associated with worse PFS in children &lt;3 years of age (hazard ratio [HR] 3.93, 95% CI 1.80-8.55; P = .0006), suggestive of sex-specific risks needing future validation. For children ≥3 years of age, disseminated disease at diagnosis was significantly associated with an inferior 5-year PFS of 39.2 ± 9.7% (HR 2.88, 95% CI 1.52-5.45; P = .0012) and 5-year OS of 49.8 ± 9.1% (HR 2.87, 95% CI 1.49-5.53; P = .0016). Conclusion Given the rarity of this tumor, prospective, collaborative international studies will be vital to improving the long-term survival of these patients.