MB-06: TREATMENT RESULTS OF MEDULLOBLASTOMA IN CHILDREN OLDER THAN 3 YEARS OF AGE ACCORDING TO MOLECULAR SUBGROUP-SPECIFIC RISK STRATIFICATION

From 2008 to 2015 years 57 pediatric patients with de novo medulloblastoma were included in trial. Average risk group (ARG) was presented by: R0M0, R1M0 (WNT, SHH desmoplastic variant and MBEN); high risk group (HRG): M + , R1 (different from ARG), LCA (non-WNT), C-MYC/N-MYC amplifications, iso17q (Group3). Children of ARG underwent therapy like ARG-SJMB03; for HRG: arm A - like HRG-SJMB03, arm B - MTX-OPEC / radiation therapy (CSI 24.4 or 36 Gy + local – up to 54Gy) / 2 cycles thiophosphamide/carboplatin with auto SCT. Twenty four children were included in ARG, 33 – in HRG (arm A 22, arm B 11). R1 status was revealed in 33.3% patients, M+ – 36.8%, LCA variant - 7%, WNT subgroup - 7%, SHH – 23.3%, Group3 – 20.9%, Group 4 – 48.8%, C-MYC/N-MYC amplification - 3.5%, iso17q (Group3) - in 7 out of 9 cases (77.8%) of whom 5 M + , 5 R1. In ARG EFS, PFS were 82.1 ± 9.4%, a median follow-up 37.2 ± 5.6 months; for HRG arm A: EFS 53.5 ± 13%, PFS 59.3 ± 13.7%, a median follow-up 35.2 ± 5.3 months; for HRG arm B: EFS, PFS was 100%, a median follow-up 16.2 ± 2.8 months. Three events were revealed in ARG, 8 – in HRG (arm A). Events: late relapse - 5 cases (only in Group4), early relapse - 3, progression - 1 with C-MYC amplification. Six patients with iso17q (Group3), 1 with N-MYC amplification are alive. Treatment related mortality was 3.5% due to septic complications.