P10.06.A PROGNOSTIC FACTORS IN CHILDREN WITH SHH MEDULLOBLASTOMA.

Abstract RELEVANCE Medulloblastomas of the SHH account for 30% of all medulloblastomas in children and are a heterogeneous group in the histological and molecular landscape. The prognosis of the disease depends on many factors. OBJECTIVE To evaluate the factors influencing the prognosis of SHH medulloblastoma in children. MATERIAL AND METHODS The analysis of treatment results of 111 patients aged 0.5 to 17 years inclusive with a confirmed diagnosis of medulloblastoma subgroup SHH, who received treatment from 1994 to 2021, was conducted. All patients underwent tumor resection, depending on age, children under 5 years of age received polychemotherapy with or without HDCT. Patients over 5 years of age received chemoradiation therapy according to various protocols. An assessment was made of clinical (age, presence of residual tumor more than 1.5 cm3, metastasis) and molecular factors (germinal mutations TP 53, PTCH, SUFU), MYCN amplification, GLI 2. TP 53 mutations were combined in MYCN in 47.6% and GLI 2 in 38.1 %. RESULTS Prognostic factors that influenced survival: histological type of tumor, germline mutations in the TP53 gene, amplification of the NMYC gene in the tumor, mutation in the GLI 2 gene. The best 5-year survival was in patients with MBEN and DMB: OS - 87.4% and 85.7%, PFS - 87.5% and 81.8%, respectively. Patients with AMB and TP 53 mutation had a poor prognosis - OS -25%, PFS - 16.1%; similarly with TP 53 mutation: OS - 37%, PFS - 31%, as well as MYCN amplification: OS - 35.3%, PFS - 25.9%. Five-year survival in patients in the standard risk group was: OS - 90.2%, PFS 89.2%, in the low-risk group OS - 83.3%, PFS - 83.3%. CONCLUSION The prognosis was not affected by gender, age, volume of resection, presence of metastases, presence of PTCH 1, SUFU, SMO mutations. The histological variant of medulloblastoma and the presence of MYCN amplification, as well as the germline mutation TP 53 and mutation in the GLI 2 gene, had a significant impact on the prognosis.