# Neuroendocrine tumour grade (Ki-67) and WHO classification

Source: https://nuclide.cc/terms/net-grade-ki67/  
Nuclide record `net-grade-ki67` (Term). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

How fast the tumour cells are dividing, measured by Ki-67 staining, separates slow-growing neuroendocrine tumours from aggressive neuroendocrine carcinomas and decides the treatment.

## Summary

WHO 2019/2022: well-differentiated NET grade 1 (Ki-67 <3%), grade 2 (3-20%), grade 3 (>20%, well-differentiated); poorly differentiated neuroendocrine carcinoma (NEC, small- or large-cell) is a separate lineage treated like small-cell lung cancer. Grade drives choice among somatostatin analogues, PRRT, targeted therapy and chemotherapy.

## Fields

- Kind: Term
- Last checked: 2026-09-07

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Neuroendocrine_tumor
- Wikipedia: https://en.wikipedia.org/wiki/Neuroendocrine_tumor

## Connected records

- indications: [Grade 3 well-differentiated neuroendocrine tumour](https://nuclide.cc/indications/grade-3-net/), [Lung neuroendocrine tumours (typical and atypical carcinoid)](https://nuclide.cc/indications/lung-net/), [Neuroendocrine tumours](https://nuclide.cc/indications/neuroendocrine/), [Pancreatic neuroendocrine tumours](https://nuclide.cc/indications/pancreatic-net/), [Small intestinal neuroendocrine tumours](https://nuclide.cc/indications/small-intestinal-net/), [Small-cell lung cancer](https://nuclide.cc/indications/sclc/)

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