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Clinical calculator summary

NET Grade / WHO 2019

The WHO Classification of Neuroendocrine Neoplasms (NENs) grades tumors based on proliferative activity, measured by Ki-67 index or Mitotic Count.

Evidence-based context for fast calculator use

Purpose:
WHO 2019 NET grading classifies neuroendocrine tumors by Ki-67 index and mitotic count to guide treatment selection and prognosis estimation.
Population:
patients with the adrenal or neuroendocrine tumor pathology described by the scoring system
Factors:
Ki-67 Index, Mitotic Count
Reference:
WHO Classification of Tumours Editorial Board. Digestive System Tumours. 5th ed. Lyon: IARC; 2019. / Endocrine and Neuroendocrine Tumours. 5th ed. Lyon: IARC; 2022.
HomeNET Grade / WHO 2019
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NET Grade / WHO 2019

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Clinical Context & Background

The WHO Classification of Neuroendocrine Neoplasms (NENs) grades tumors based on proliferative activity, measured by Ki-67 index or Mitotic Count. This grading is critical for prognosis and treatment selection. If Ki-67 and Mitotic Count are discordant, the higher grade is assigned.
Primary Source EvidenceWHO Classification of Tumours Editorial Board. Digestive System Tumours. 5th ed. Lyon: IARC; 2019. / Endocrine and Neuroendocrine Tumours. 5th ed. Lyon: IARC; 2022.
Formula Logic
Grade determined by higher of Ki-67 or Mitoses.

Reference Data

GradeMitotic Count (/2mm²)Ki-67 Index
G1 (Low Grade)< 2< 3%
G2 (Intermediate)2 - 203 - 20%
G3 (High Grade)> 20> 20%

Clinical Workflow

Use, Interpret, And Continue The Patient Pathway

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

When To Use

  • Use NET Grade / WHO 2019 when wHO 2019 NET grading classifies neuroendocrine tumors by Ki-67 index and mitotic count to guide treatment selection and prognosis estimation.
  • 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 G1 (Low Grade) through G3 (High Grade).
  • A boundary result should prompt input verification and clinical review rather than false precision.

What To Do Next

  • Confirm specimen adequacy, expert endocrine pathology, hormonal function, imaging, stage, and molecular context.
  • Document the inputs, result, timing, and clinical context so the assessment can be reproduced.

Limitations

  • Pathology criteria can be subtype-specific and should not be extrapolated between adrenal and neuroendocrine neoplasms.
  • The result supports clinician judgment and does not independently determine treatment.

Validated Population

patients with the adrenal or neuroendocrine tumor pathology described by the scoring system

How to apply this result

For a representative case, verify Ki-67 Index, Mitotic Count, calculate the result, and confirm that its classification matches the highlighted reference band before continuing the disease-specific pathway.

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Frequently Asked Questions

When should NET Grade / WHO 2019 be used?

Use it for patients with the adrenal or neuroendocrine tumor pathology described by the scoring system when all required inputs and the intended clinical setting are confirmed.

Can NET Grade / WHO 2019 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.