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CNS: Low-grade glioma risk stratification

Free question published 26 August 2026

Central nervous systemLow-grade glioma risk stratification

A 38-year-old man presents after a single seizure. MRI shows a non-enhancing left insular lesion; biopsy confirms a diffuse astrocytoma, IDH-mutant, WHO grade 2. He undergoes a gross total resection and postoperative MRI shows no residual tumour. He has no neurological deficit and KPS 100. Which management strategy is most appropriate?

  1. AImmediate whole-brain radiotherapy
  2. BAdjuvant temozolomide alone
  3. CImmediate radiotherapy followed by 6 cycles of PCV
  4. DImmediate radiotherapy with concomitant and adjuvant temozolomide
  5. EActive monitoring with serial MRI, deferring further treatment

Why E is correct

For a patient aged around 40 or under with an IDH-mutant low-grade glioma and no residual tumour on postoperative MRI, NICE NG99 (recommendation 1.2.8) supports active monitoring. EORTC 22845 showed early radiotherapy improves progression-free survival but not overall survival, so deferring radiotherapy in low-risk patients is reasonable and avoids early treatment-related toxicity.

And why the others are not

  • AIncorrect: whole-brain radiotherapy has no role in a localised low-grade glioma.
  • BIncorrect: temozolomide monotherapy is not the recommended adjuvant approach for low-grade glioma; the chemotherapy evidence base favours PCV in higher-risk disease.
  • CIncorrect: radiotherapy plus PCV is reserved for higher-risk low-grade glioma (age around 40 or over, or residual tumour), neither of which applies here.
  • DIncorrect: this is a high-grade glioma regimen and is not indicated for a fully resected low-risk grade 2 tumour.

Source NICE NG99 — Brain tumours (primary) and brain metastases in adults — National Institute for Health and Care Excellence. Brain tumours (primary) and brain metastases in over 16s. NICE guideline NG99. Published 11/07/2018, updated 29/01/2021.

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