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Clinical calculator summary

WHO CNS Tumor Grade (2021)

The 2021 WHO Classification of Tumors of the Central Nervous System classifies tumors into Grades 1 to 4 based on histology and molecular markers.

Evidence-based context for fast calculator use

Purpose:
WHO 2021 CNS Tumor Grading classifies central nervous system tumors into grades 1-4 using histology and molecular markers to guide treatment.
Population:
patients with primary or metastatic central nervous system disease in the setting described by the model
Factors:
Select Tumor Features / Histology
Reference:
Louis DN, et al. The 2021 WHO Classification of Tumors of the Central Nervous System: a summary. Neuro Oncol. 2021;23(8):1231-1251.
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WHO CNS Tumor Grade (2021)

Clinical Context & Background

The 2021 WHO Classification of Tumors of the Central Nervous System classifies tumors into Grades 1 to 4 based on histology and molecular markers. Unlike previous editions, grading is now done within tumor types (e.g., IDH-mutant Astrocytoma is Grade 2-4) rather than across types. Higher grades indicate increased aggressiveness and poorer prognosis.
Primary Source EvidenceLouis DN, et al. The 2021 WHO Classification of Tumors of the Central Nervous System: a summary. Neuro Oncol. 2021;23(8):1231-1251.
Formula Logic
Classification based on malignancy, mitoses, necrosis, and molecular features.

Reference Data

GradeBiological BehaviorPrognosis
Grade 1Low proliferative potentialExcellent (Curative with surgery)
Grade 2Infiltrative, low mitotic activityGood (Often recur, can progress)
Grade 3Histological malignancyIntermediate (Aggressive, adjuvant tx needed)
Grade 4Necrosis/Microvascular proliferationPoor (Very aggressive, rapid evolution)

Clinical Workflow

Use, Interpret, And Continue The Patient Pathway

Expand for workflow guidance, limitations, examples, and related next steps.

When To Use

  • Use WHO CNS Tumor Grade (2021) when wHO 2021 CNS Tumor Grading classifies central nervous system tumors into grades 1-4 using histology and molecular markers to guide treatment.
  • Confirm that the patient, diagnosis, disease phase, and available inputs match the cited model before calculation.

How To Interpret

  • Interpret the displayed result using the calculator-specific formula and reference table, spanning Grade 1 through Grade 4.
  • A boundary result should prompt input verification and clinical review rather than false precision.

What To Do Next

  • Confirm primary histology, molecular classification, number and location of lesions, extracranial disease, performance status, and treatment era.
  • Document the inputs, result, timing, and clinical context so the assessment can be reproduced.

Limitations

  • Generic brain-metastasis and disease-specific GPA models should not be interchanged.
  • The result supports clinician judgment and does not independently determine treatment.

Validated Population

patients with primary or metastatic central nervous system disease in the setting described by the model

How to apply this result

For a representative case, verify Select Tumor Features / Histology, calculate the result, and confirm that its classification matches the highlighted reference band before continuing the disease-specific pathway.

Neuro-Oncology hubContinue to related calculators and clinical workflow resources.

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Frequently Asked Questions

When should WHO CNS Tumor Grade (2021) be used?

Use it for patients with primary or metastatic central nervous system disease in the setting described by the model when all required inputs and the intended clinical setting are confirmed.

Can WHO CNS Tumor Grade (2021) determine treatment by itself?

No. Interpret the result with the cited evidence, complete clinical assessment, current guidelines, and patient-specific goals.

Evidence-based oncology decision support. Verify with clinical guidelines.