Diffuse Gliomas Clinical Practice Guidelines (EANO, 2021)

European Association of Neuro-Oncology

This is a quick summary of the guidelines without analysis or commentary. For more information, go directly to the guidelines by clicking the link in the reference.

January 29, 2021

Clinical practice guidelines on the diagnosis and treatment of diffuse gliomas of adulthood were issued in December 2020 by the European Association of Neuro-Oncology (EANO).[1]

History and Clinical Examination

Consider using the Karnofsky performance score (KPS), neurological function, age, and individual risks and benefits for clinical decision-making.

There is no major role for screening or prevention in patients with gliomas.

Genetic counselling should be offered to patients with relevant germline variants or suspected hereditary cancer syndromes; this may result in a referral for molecular genetic testing.

Preoperative Diagnostics

The first diagnostic imaging modality of choice is MRI, with or without a gadolinium-based contrast agent.

In the event increased abnormalities are noted on neuroimaging findings in the first months after local therapeutic interventions (eg, radiotherapy) and after any experimental local treatments, consider the possibility of pseudoprogression.

Tissue Acquisition

Only in very exceptional circumstances should one consider making clinical decisions without having first obtained a tissue diagnosis.

Integrated Histomolecular Classification

The recommended glioma classification systems are the most recent WHO Classification of Tumors of the Central Nervous System, along with the cIMPACT-NOW updates.

For diagnostic assessment of diffuse gliomas, it is recommended to routinely perform immunohistochemistry for mutant IDH1 R132H protein and nuclear expression of ATRX.

In the event immunohistochemistry results for IDH1 R132H are negative, the recommended next step is sequencing of IDH1 codon 132 and IDH2 codon 172 for all WHO grade 2 and 3 diffuse astrocytic and oligodendroglial gliomas. This also applies to all glioblastomas in patients younger than 55 years, in order to integrate diagnoses according to the WHO classification and to guide treatment decisions.

Determine 1p/19q codeletion status in all IDH-mutant gliomas with retained nuclear expression of ATRX.

Determine MGMT promoter methylation status in glioblastoma in order to aid in decision-making for the use of temozolomide; this is most notable in frail or elderly patients.

Explore CDKN2A/B homozygous deletions in IDH-mutant astrocytomas.

In IDH-wild-type diffuse gliomas that lack the microvascular proliferation and necrosis criteria as histological features of WHO grade 4, test for (1) combined chromosome 7 gain and chromosome 10 loss (+7/–10 signature), (2) EGFR amplification, and (3) TERT promoter mutation, in order to allow for a diagnosis of IDH-wild-type glioblastoma.

Perform an assessment of the H3 K27M status in diffuse gliomas involving the midline.

Consider assessing BRAF V600 mutations in IDH-wild-type diffuse gliomas.

General Therapy Recommendations

Considering that the extent of resection is associated with prognosis, efforts to obtain complete resections are justified for all glioma entities.

The current surgical approach to gliomas dictates that preventing new permanent neurological deficits is of higher priority than the extent of resection.

Specific Therapy Recommendations


For IDH-mutant astrocytomas, WHO grade 2, that require further treatment, the standard of care is resection, if feasible, or performing a biopsy followed by involved-field radiation therapy and maintenance PCV (procarbazine, lomustine [CCNU], vincristine) polychemotherapy.

For IDH-mutant astrocytomas, WHO grade 3, the standard of care is resection, if feasible, or performing a biopsy followed by involved-field radiation therapy and maintenance chemotherapy with temozolomide.

For IDH-mutant and 1p/19q-codeleted oligodendrogliomas, WHO grade 2, that require additional treatment, use radiation therapy followed by PCV polychemotherapy.

For IDH-mutant and 1p/19q-codeleted oligodendrogliomas, WHO grade 3, use radiation therapy followed by PCV polychemotherapy.

If progression occurs after surgery and radiation therapy, the standard of care for most patients with IDH-mutant gliomas, WHO grade 2 or 3, is temozolomide chemotherapy.


For IDH-wild-type glioblastoma in patients younger than 70 years who have a KPS of 70 or greater, the standard of care is resection, if feasible, or performing a biopsy followed by involved-field radiation therapy, concomitant radiation therapy, and six cycles of maintenance chemotherapy with temozolomide.

Regarding temozolomide activity, it may only be active in MGMT promoter-methylated tumors. Its activity in MGMT promoter-unmethylated tumors is considered marginal.

Treat patients who are elderly and who are not considered candidates for temozolomide chemoradiotherapy on the basis of their MGMT promoter methylation status, using radiation therapy (eg, 15 × 2.66 Gy) or temozolomide (5 of 28 days) alone.

The standards of care at recurrence are not well-defined. Consider surgery and radiation therapy. Options for pharmacotherapy can include temozolomide rechallenge, nitrosourea regimens, and bevacizumab (with consideration of the country-specific label). The impact on overall survival remains unproven. Consider recruitment into appropriate clinical trials, when available.

For more information, see Brainstem Gliomas, Oligodendroglioma, Glioblastoma Multiforme, and Astrocytoma.

For more Clinical Practice Guidelines, go to Guidelines.


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