Wilms Tumor - Childhood: Stages

Approved by the Cancer.Net Editorial Board, 01/2022

ON THIS PAGE: You will learn about how doctors describe a tumor’s growth or spread. This is called the stage. Use the menu to see other pages.

What is cancer staging?

Staging is a way of describing where the tumor is located, if or where it has spread, and whether it is affecting other parts of the body.

Doctors use diagnostic tests to find out the tumor's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor recommend the best kind of treatment and can help predict a child's prognosis, which is the chance of recovery. There are different stage descriptions for different types of tumors.

This page provides detailed information about the stage groupings and prognostic factors used to describe a Wilms tumor.

Stage groups for a Wilms tumor

A Wilms tumor is staged based on the results of surgery, analysis of the tumor cells (see Diagnosis), and whether the cancer has spread. There are 5 stages: Stage I through V (1 through 5.) The stage provides a common way of describing the tumor, so doctors can work together to plan the best treatments.

Stage I: The tumor is found in 1 kidney and can be completely removed with surgery.

Stage II: Cancer is found in the kidney and in the fat, soft tissue, or blood vessels near the kidney. It may have spread to the renal sinus. The renal sinus is the part of the kidney where blood and fluid enter and exit the organ. The tumor can be completely removed with surgery.

Stage III: Cancer is found in areas near the kidney and cannot be completely removed with surgery. The tumor may have spread to nearby organs and blood vessels or throughout the abdomen and to nearby lymph nodes. Lymph nodes are small, bean-shaped organs that help fight infection. Stage III cancer has not spread outside the abdomen.

Stage IV: Cancer has spread to other, more distant organs, such as the lungs, liver, bones, and brain, or to lymph nodes outside the abdomen. This is called metastasis.

Stage V: Cancer cells are in both kidneys at the same time. The tumor in each kidney is staged separately.

Refractory: A refractory Wilms tumor is a tumor that does not shrink during or after treatment.

Recurrent: A recurrent Wilms tumor is a tumor that has come back after treatment. The tumor may come back in the area where it first started or in another part of the body. If the tumor does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.

Source: National Wilms Tumor Study Group Staging System.

Prognostic factors

The 2 most important factors that predict the prognosis of a child with a Wilms tumor are:

  • The histology of the tumor. This is what the tumor cells look like under a microscope. A favorable histology is usually linked to a better prognosis. Tumors with an anaplastic histology are less likely to be successfully treated with chemotherapy and/or radiation therapy and require more aggressive treatment. Anaplastic means the cells divide rapidly and do not resemble healthy cells. About 10% of Wilms tumors have an anaplastic histology. Tumors in people who are 12 to 16 years old are more likely to be anaplastic.

  • The stage of the tumor. In general, a low-stage cancer is more likely to be successfully treated than a high-stage cancer. This is particularly true for Wilms tumors with an anaplastic histology. The stages are the same for tumors, regardless of histology.

Return to top

Information about the cancer’s stage and histology will help the doctor recommend a specific treatment plan. The next section in this guide is Types of Treatment. Use the menu to choose a different section to read in this guide.