# Wilms tumour staging (Children's Oncology Group)

Source: https://onco.cc/terms/wilms-tumour-staging/  
OnCo record `wilms-tumour-staging` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Wilms tumour is staged I to V from the scans and the operation together: from a tumour removed whole inside the kidney (I), through spread in the abdomen (III) and distant spread (IV), to both kidneys involved (V).

## Summary

The NCI's health professional summary gives the staging system developed by the National Wilms Tumor Study Group and still used by the Children's Oncology Group, which combines imaging with surgical and pathological findings; the histology (favourable or anaplastic) is stated alongside the stage. Stage I (43% of patients): limited to the kidney, completely removed, capsule intact, not ruptured or biopsied beforehand, nodes negative. Stage II (20%): extends beyond the kidney but completely removed with clear margins. Stage III (21%): tumour left in the abdomen after surgery, including involved abdominal or pelvic nodes, peritoneal spread, rupture or spill, biopsy before removal, or removal in more than one piece. Stage IV (11%): spread through the blood (lung, liver, bone, brain) or to nodes outside the abdomen and pelvis. Stage V (5%): both kidneys at diagnosis. Lymph node sampling is strongly recommended for all patients, even when the nodes look normal.

## Fields

- Kind: Term
- Last checked: 2026-11-04
- Also known as: Wilms tumour staging; Wilms tumor staging; NWTS staging; COG renal tumour staging

## Sources

- National Cancer Institute, Wilms tumor and other childhood kidney tumors treatment (PDQ), health professional version: stage information: https://www.cancer.gov/types/kidney/hp/wilms-treatment-pdq

## Connected records

- terms: [Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC)](https://onco.cc/terms/staging-systems/), [Wilms tumour risk markers (anaplasia, 1p/16q loss, 1q gain, SIOP and COG risk groups)](https://onco.cc/terms/wilms-risk-markers/)
- cancers: [Wilms tumour (nephroblastoma)](https://onco.cc/cancers/wilms-tumor/)

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