Molecular Grouping and Outcomes of Young Children with Newly Diagnosed Ependymoma Treated on the Multi-Institutional SJYC07 Trial. Neuro-oncology Upadhyaya, S. A., Robinson, G. W., Onar-Thomas, A., Orr, B. A., Billups, C. A., Bowers, D. C., Bendel, A. E., Hassall, T., Crawford, J. R., Partap, S., Fisher, P. G., Tatevossian, R. G., Seah, T., Qaddoumi, I. A., Vinitsky, A., Armstrong, G. T., Sabin, N. D., Tinkle, C. L., Klimo, P., Indelicato, D. J., Boop, F. A., Merchant, T. E., Ellison, D. W., Gajjar, A. 2019


BACKGROUND: This report documents the clinical characteristics, molecular grouping and outcome of young children with ependymoma treated prospectively on a clinical trial.METHODS: Fifty-four children (aged = 3 years) with newly diagnosed ependymoma were treated on the SJYC07 trial with maximal safe surgical resection, 4 cycles of systemic chemotherapy, consolidation therapy using focal conformal radiation therapy (RT) (5-mm clinical target volume), and 6 months of oral maintenance chemotherapy. Molecular groups were determined by tumor DNA methylation using Infinium Methylation EPIC BeadChip and profiled on DKFZ/German molecularneuropathology2.0 classifier.RESULTS: One of the 54 study patients had metastases (CSF+) at diagnosis. Gross- or near-total resection was achieved in 48 (89%) patients prior to RT. At a median follow-up of 4.4 years (range, 0.2-10.3 years), 4-year progression-free survival (PFS) was 75.1% ± 7.2%, and overall survival was 92.6% ± 4.4%. The molecular groups showed no significant difference in PFS [4-year estimates: PF-EPN-A (42/54), 71.2% ± 8.3%; ST-EPN-RELA (8/54), 83.3% ± 17.0%; ST-EPN-YAP (4/54), 100%, p=0.22]. Subtotal resection prior to RT was associated with an inferior PFS compared to gross- or near-total resection (4-year PFS: 41.7% ± 22.5% vs. 79.0% ± 7.1%, p=0.024) as was PF-EPN-A group with 1q gain (p=0.05). Histopathologic grading was not associated with outcomes (classic vs anaplastic; p=0.89).CONCLUSIONS: In this prospectively treated cohort of young children with ependymoma, ST-EPN-RELA tumors had a favorable outcome than reported from retrospective data. Histological grade did not impact outcome. PF-EPN-A with 1q gain, and sub-total resection were associated with inferior outcomes.

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