RADT-27. REPORT OF 9 CASES OF EMBRYONAL TUMORS OF THE CENTRAL NERVOUS SYSTEM WITH MULTILAYERED ROSETTES (ETMR)

Abstract OBJECTIVE Embryonal Tumors of the Central Nervous System with Multilayered Rosettes (ETMR) are rare, and there’s no standard treatment protocol. This article reports on the current treatment status and prognosis of ETMR in our hospital. METHODS We retrospectively collected patients with ETMR who received treatment in the Oncology Department of Guangdong sanjiu Brain Hospital from January 2017 to January 2021, analyzed their clinical data. RESULTS Among 31 cases of central nervous system embryonic tumors (excluding medulloblastoma and ATRT), 9 (29.03%) were ETMR. The median age at diagnosis was 3 years old (1-15), and the male to female ratio was 4:5. Among them, 5 cases were accompanied by C19MC gene variation. Tumor location:6 was in supratentorial, 1 in the pineal region, 1 in the pons, 1 in the cerebellopontine. Eight patients underwent surgical resection at the first diagnosis, with 6 cases of total resection, 1 case of partial resection, and 1 case of biopsy. One case was misdiagnosed as a germinoma in the pineal region at the initial. After recurrence, surgical resection was performed to confirm the pathology as ETMR. One case was misdiagnosed as glioblastoma during the first surgery. The initial treatment for 4 patients after surgery was radiotherapy combined with concurrent chemotherapy. Recurrence patterns: 2 cases were intracranial dissemination, 2 cases were local recurrence, 1 was spinal cord dissemination. One patient did not receive treatment after surgery and tumor recurrence 3 months later. Survival analysis: The median survival time was 20 months. The 1-year progression-free survival rate (PFS) and overall survival rate (OS) were 22% and 61%, and the 2-year overall survival rate (OS) was 31%. CONCLUSION ETMR has a low incidence and poor prognosis. It is easy to misdiagnose and NGS is necessary to assist diagnosis when needed. More effective treatment methods need to be explored.