MDB-13. CURRENT STATUS OF DIAGNOSIS AND TREATMENT FOR HIGH-RISK STAGE M2/M3 NON-WNT SUBTYPES MEDULLOBLASTOMA IN SOUTH CHINA

OBJECTIVE: To analyze the current diagnosis and treatment status of high-risk stage M2/M3 non-WNT types medulloblastoma in China, and explore the optimal treatment option. METHODS: The inclusion criteria were as follows: (1) age≤18 years old; (2) medulloblastoma was diagnosed by surgical pathology at initial diagnosis; (3) molecular subtyping: non-WNT types; (4) Chang’s stage: M2/M3. Exclusion criteria: cases of WNT molecular subtype were excluded. Clinical data of the patients were included in the analysis, and the overall survival rate and the survival difference between each molecular subtype group were analyzed. RESULTS: A total of 247 children with medulloblastoma under 18 years old were admitted to Guangdong Sanjiu Brain Hospital from January 1, 2017, to December 31, 2022. In line with the inclusion criteria, a total of 31 children were enrolled in the present study. All patients were treated with conventional radiotherapy and chemotherapy according to the Chinese Guidelines for diagnosing and treating medulloblastoma. The median age of enrolled patients was 5 years (range 1-15 years), counting 21 males and 10 females. According to the Chang staging system, 16 patients were in the M2 stage, and 15 were in the M3 stage. 8, 11, and 12 patients were in Group 3, Group 4, and SHH molecular subgroups, respectively. Survival analysis showed that the 5-year survival rate of 31 children was 50.2%, and there was no significant difference in the 5-year survival rate between different molecular subgroups (p=0.57). CONCLUSIONS: The overall prognosis of high-risk M2 and M3 staged medulloblastoma is poor. Except for the WNT subtype, the optimal treatment strategy for medulloblastoma with metastasis is still worth exploring.