1p/19q codeletion combined with IDH mutation defines oligodendroglioma (WHO CNS 2021 5th...
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| ID | BMA-1P19Q-CODELETION-LGG |
|---|---|
| Tipo | Relevância terapêutica |
| Estado | reviewed 2026-05-06 | pending_clinical_signoff | actionability review required |
| Doenças | DIS-GLIOMA-LOW-GRADE |
| Fontes | SRC-EANO-GLIOMA-2022 SRC-NCCN-CNS-2025 |
Fatos de ação
| Biomarcador | BIO-1P19Q-CODELETION |
|---|---|
| Variante | Concurrent loss of 1p and 19q (codeletion) by FISH or SNP array in the context of IDH-mutant diffuse glioma (WHO grade 2 or 3). IDH mutation must be confirmed separately. Codeletion in IDH-wildtype context does NOT qualify. |
| Doença | DIS-GLIOMA-LOW-GRADE |
| Nível ESCAT | IA |
| Combinações recomendadas | RT + PCV (procarbazine 60 mg/m² d8-21, lomustine 110 mg/m² d1, vincristine 1.4 mg/m² d8+29, q6w x6) — preferred per RTOG 9802 (Category 1), RT + temozolomide (TMZ 75 mg/m² concurrent, then 150-200 mg/m² d1-5 q28d adjuvant x12) — alternative, less neurotoxic |
| Contraindicated monotherapy | RT isoladamente (inferior ao RT+PCV em 1p/19q-codeletado oligodendroglioma por dados de fase III), Bevacizumab (anti-VEGF — não há evidência de benefício no LGG mutante IDH) |
| Resumo das provas | 1p/19q codeletion combined with IDH mutation defines oligodendroglioma (WHO CNS 2021 5th edition). Oligodendroglioma has the best prognosis among diffuse gliomas and is uniquely chemosensitive. Two landmark phase III trials establish PCV chemotherapy added to radiotherapy as standard of care: EORTC 26951 (van den Bent et al. JCO 2013 / 12-yr update Cairncross JCO 2013): 374 pts, anaplastic oligodendroglioma; RT alone vs RT + PCV; in the 1p/19q-codeleted subgroup: mOS 14+ yr with RT+PCV vs 9.3 yr RT alone (HR ~0.5). Benefit confined to codeleted tumors. RTOG 9802 (Shaw et al. NEJM 2012 / 10-yr update): low-risk LGG subset; RT+PCV vs RT alone; 10-yr OS 73.8% vs 60.1% (HR 0.59, p=0.003). 1p/19q-codeleted patients derived greatest benefit. For grade 2 oligodendroglioma, temozolomide (TMZ) is an alternative to PCV (less neurotoxicity, shorter course) — EORTC 22033-26033 trial showed no OS advantage of TMZ monotherapy over RT but equal outcomes in codeleted tumors. NCCN CNS 2025: PCV (Category 1) preferred; TMZ acceptable. The biomarker (1p/19q codeletion + IDH mutation) governs both diag... |
Notas
ESCAT IA. The combination of IDH mutation + 1p/19q codeletion is one of the strongest molecular biomarker-to-treatment relationships in neuro-oncology: it predicts both diagnosis (oligodendroglioma, definitionally) and chemosensitivity (PCV response). ATRX mutation status (IHC) is used to EXCLUDE astrocytoma when codeletion is found — the two markers are mutually exclusive per WHO CNS 2021. Testing workflow: IDH first (IHC ± sequencing) → if IDH-mutant → 1p/19q FISH or SNP array → if codeleted = oligodendroglioma → PCV+RT. If not codeleted and ATRX lost = astrocytoma → different treatment pathway. TERT promoter mutation co-occurs in ~95% of oligodendrogliomas and may reinforce the diagnosis when 1p/19q FISH is equivocal.
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