ON THIS PAGE: You will learn about how doctors describe a tumor’s growth or spread. This is called the stage. To see other pages, use the menu on the side of your screen.
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 to decide what kind of treatment is best and can help predict a child's prognosis, which is the chance of recovery. There are different stage descriptions for different types of tumors. Wilms tumor is staged based on the results of surgery, analysis of the tumor cells (see the Diagnosis  section), and whether it has spread.
The two most important factors that predict the prognosis for a child with Wilms tumor are:
- What the tumor cells look like under a microscope, called the histology of the tumor. A favorable histology is usually associated with a better prognosis. An anaplastic histology is less likely to be successfully treated with chemotherapy and/or radiation therapy and requires more aggressive treatment.
- The stage of the tumor. Early-stage cancer is more likely to be successfully treated than later-stage cancer.
Stage I. The tumor is in one 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 part of the kidney through which blood and fluid enter and exit the organ, called the renal sinus. 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 tiny, 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 lymph nodes outside the abdomen.
Stage V. Cancer cells are in both kidneys at the same time. The tumor in each kidney is staged separately.
Recurrent. A recurrent 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 there is a recurrence, the cancer may need to be staged again (re-staging) using the system above.
Source: National Wilms Tumor Study Group  Staging System.
Information about the tumor’s stage will help the doctor recommend a treatment plan. The next section helps explain the treatment options for this type of tumor. Use the menu on the side of your screen to select Treatment Options, or you can select another section, to continue reading this guide.