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Gliomas and glioblastoma in adults
Glioblastoma (IDH wild-type) is managed by maximal safe resection, then 60 Gy radiation with temozolomide and then adjuvant temozolomide; MGMT promoter methylation predicts benefit from temozolomide, and IDH and 1p/19q define the other gliomas.
Why it matters in the exam
The topic appears in the exam in questions on standard glioblastoma treatment, treatment of an older patient, the meaning of MGMT methylation, the mechanism of temozolomide and tumour types with IDH mutations. Questions on pseudoprogression and PCP prophylaxis during treatment also appear.
The 2021 World Health Organization classification is the basis of questions: glioblastoma is now defined only as an IDH wild-type tumour, astrocytoma is IDH-mutant, and oligodendroglioma is IDH-mutant with 1p/19q codeletion. In an older frail patient the choice between short-course radiation, temozolomide alone or both depends on MGMT and performance status.
Key points
- Glioblastoma is an IDH wild-type tumour, treated by maximal resection followed by 60 Gy radiation with temozolomide.
- MGMT promoter methylation silences the repair enzyme and predicts greater benefit from temozolomide.
- In an older patient give short-course radiation, and in an older frail patient choose by MGMT between temozolomide alone and radiation alone.
- IDH-mutant gliomas have a better prognosis, and 1p/19q defines oligodendroglioma.
- In supportive care: dexamethasone for oedema, levetiracetam only for seizures, and PCP prophylaxis during chemoradiation.
Summary table
| Situation | Treatment | Exam detail |
|---|---|---|
| Glioblastoma, fit patient | Maximal safe resection, radiation 60 Gy in 30 fractions with daily temozolomide, then temozolomide for 6 cycles | Tumour treating fields (TTFields) may be added |
| Glioblastoma, older patient | Short-course radiation 40 Gy in 15 fractions with temozolomide | Older and frail: MGMT methylated — temozolomide alone; unmethylated — short-course radiation alone |
| MGMT | The enzyme repairs damage that temozolomide creates on guanine | Promoter methylation silences the gene — less repair and more benefit from temozolomide |
| IDH-mutant astrocytoma or oligodendroglioma | Surgery, then radiation with chemotherapy (PCV or temozolomide) in high risk | Vorasidenib (IDH inhibitor) for grade 2 tumours after surgery, to delay radiation |
| Recurrence | Repeat surgery, lomustine, bevacizumab or re-irradiation | Bevacizumab improves progression-free time and oedema, not overall survival |
| Pseudoprogression | Worsening on imaging within 12 weeks after radiation | More common with methylated MGMT; do not rush to change treatment |
| Supportive care | Dexamethasone for oedema, levetiracetam for seizures, PCP prophylaxis during temozolomide with radiation | No seizure prophylaxis for those who have not had a seizure |
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Sources
- NCCN Clinical Practice Guidelines in Oncology: Central Nervous System Cancers, 2026 — Glioma and glioblastoma
- WHO Classification of Tumours of the Central Nervous System, 5th ed. (2021) — Adult-type diffuse gliomas
- EANO Guideline on the diagnosis and management of diffuse gliomas of adulthood, 2021 — Treatment recommendations
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.