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MEDB-41. Identifying a subgroup of patients with early childhood sonic hedgehog-activated medulloblastoma with unfavorable prognosis after treatment with radiation-sparing regimens including intraventricular methotrexate

2022; Oxford University Press; Volume: 24; Issue: Supplement_1 Linguagem: Inglês

10.1093/neuonc/noac079.415

1523-5866

Svenja Tonn, Denise Obrecht, Martin Sill, Michael Spohn, Till Milde, Torsten Pietsch, Brigitte Bison, Björn-Ole Juhnke, Nina Struve, Carsten Friedrich, André O. von Bueren, Nicolas U. Gerber, Martin Benesch, Natalie Jäger, Marcel Kool, Andrey Korshunov, Ulrich Schüller, Stefan M. Pfister, Stefan Rutkowski, Martin Mynarek,

Hedgehog Signaling Pathway Studies

Abstract PURPOSE/METHODS: Clinical and molecular risk factors in 142 patients <5 years with desmoplastic medulloblastoma (DMB) or medulloblastoma with extensive nodularity (MBEN) were investigated. Patients were diagnosed between 1992 and 2020 and treated with radiation-sparing approaches, 131 with intraventricular methotrexate. 14 patients with metastatic disease received high-dose chemotherapy. DNA methylation profiles of 77 sonic hedgehog (SHH)-activated medulloblastoma were reclassified according to the Heidelberg Brain Tumor Classifier Version 12.3. RESULTS: While metastatic disease or incomplete resection did not impact progression-free survival (PFS) and overall survival (OS), patients with MBEN had superior outcomes to DMB (5-year PFS 93% vs 71%, p=0.004; 5-year OS 100% vs 90%, p=0.026). Older patients had less favorable PFS (5-year PFS [>3 years] 47% vs 85% [<1 year] vs 84% [1-3 years], p<0.001). No TP53 mutations were detected (n=47). DNA methylation classification identified three subgroups: SHH-1v12.3 (n=39), SHH-2v12.3 (n=19), and SHH-3v12.3 (n=19), with distinct cytogenetic profiles (chromosome 2 gains in SHH-1v12.3, very few alterations in SHH-2v12.3, and chromosome 9q losses in SHH-3v12.3), age profiles (median age [years] SHH-1v12.3: 1.7, SHH-2v12.3: 0.9, SHH-3v12.3: 3.0, p<0.001), and histological distribution (SHH-2v12.3: 74% MBEN, SHH-1v12.3/SHH-3v12.3: 77%/79% DMB, p<0.001). PFS was more unfavorable in patients with SHH-3v12.3-medulloblastoma (5-year PFS 53% vs 86% [SHH-1v12.3] vs 95% [SHH-2v12.3], p=0.002), which remained the only risk factor on multivariable Cox regression for PFS. OS was comparable (5-year OS 94% [SHH-3v12.3] vs 97% [SHH-1v12.3] vs 100% [SHH-2v12.3], p=0.6). 8/9 patients with SHH-3v12.3-medulloblastoma received radiotherapy at relapse (6 craniospinal, 2 local [1 Gorlin syndrome, 1 BRCA2 germline mutation], 1 no radiotherapy [Gorlin syndrome]). CONCLUSION: We identify patients with an increased risk of relapse when treated with radiation-sparing approaches among children with early childhood SHH-medulloblastoma. If these tumors differ from SHH-3-medulloblastoma typically described in older children remains to be verified. Treatment recommendations need to consider cancer predisposition syndromes.