Treatment Approaches for Glioma vs Glioblastoma
The treatment of glioblastoma requires maximal safe surgical resection followed by fractionated radiotherapy (60 Gy) with concomitant and adjuvant temozolomide, while lower-grade gliomas may be managed with surgery followed by radiotherapy and PCV polychemotherapy or temozolomide, depending on molecular characteristics. 1
Understanding Glioma vs Glioblastoma
Classification and Prognostic Factors
- Gliomas: A broad category of brain tumors arising from glial cells
- IDH-mutant astrocytomas (WHO grade 2-4)
- IDH-mutant and 1p/19q-codeleted oligodendrogliomas (WHO grade 2-3)
- IDH-wild-type glioblastoma (WHO grade 4)
- Glioblastoma: The most aggressive form of glioma (WHO grade 4)
Key Prognostic Factors
- Tumor grade and molecular characteristics (IDH mutation, 1p/19q codeletion, MGMT promoter methylation)
- Age (<50 years has better prognosis)
- Performance status
- Extent of surgical resection
- Neurological function 1
Treatment Approaches for Glioblastoma (WHO Grade 4)
Surgical Management
- Maximal safe surgical resection is the initial approach 1
- Gross total resection improves prognosis when feasible 1
- For elderly patients (>65 years), resection has shown longer overall survival compared to biopsy alone 1
Radiotherapy
- Standard fractionated focal radiotherapy: 60 Gy (2 Gy × 30 fractions) 1
- For elderly patients or those with poor performance status:
Chemotherapy
- Standard regimen: Concomitant and adjuvant temozolomide 1, 3
- Concomitant phase: 75 mg/m² daily throughout radiotherapy (including weekends)
- Maintenance phase: 150-200 mg/m² for 5 days every 28 days for 6 cycles 1, 3, 2
- This approach has improved median survival to 14.6 months vs 12.1 months with radiotherapy alone 2
- Two-year survival rate increases from 10.4% to 26.5% 2
- MGMT promoter methylation testing helps identify patients more likely to benefit from temozolomide 1
- Extended temozolomide beyond 6 cycles may improve progression-free survival but has not shown significant improvement in overall survival 4
Treatment Approaches for Lower-Grade Gliomas (WHO Grade 2-3)
IDH-Mutant Astrocytomas
- WHO Grade 2: Resection as feasible followed by involved field radiotherapy and maintenance PCV polychemotherapy 1
- WHO Grade 3: Resection as feasible followed by involved field radiotherapy and maintenance temozolomide 1
IDH-Mutant and 1p/19q-Codeleted Oligodendrogliomas
- WHO Grade 2: Radiotherapy followed by PCV polychemotherapy 1
- WHO Grade 3: Radiotherapy followed by PCV polychemotherapy 1
- Oligodendrogliomas generally have better prognosis and improved response to chemotherapy compared to astrocytomas 1
Recurrent Disease Management
- Temozolomide is standard treatment at progression after surgery and radiotherapy for most IDH-mutant gliomas (WHO grade 2 or 3) 1
- Anaplastic astrocytomas are more likely to respond to chemotherapy than glioblastoma 1
- Consider repeat surgery for selected patients 1
Monitoring and Follow-up
- MRI is the preferred imaging modality for evaluation 1
- Follow-up intervals: 3-6 monthly with neurological examination and imaging 1
- Be aware of pseudoprogression: Contrast enhancement and presumed tumor progression on imaging 4-8 weeks after radiotherapy may be an imaging artifact and should be re-evaluated after 4 weeks 1
Important Considerations and Pitfalls
Pseudoprogression: Changes in blood-brain barrier permeability after radiotherapy can mimic tumor progression on imaging. Confirm with repeat MRI after 4 weeks 1
Molecular testing: MGMT promoter methylation status is crucial for predicting temozolomide benefit in glioblastoma patients 1
Elderly patients: Consider hypofractionated radiotherapy regimens and temozolomide based on MGMT status 1
Steroid management: Taper off steroid use as early as possible to minimize side effects 1
Monitoring for toxicity:
Treatment resistance: For patients failing prior chemotherapy, clinical trials should be considered as there may be no established effective regimens available 1