When doctors suspect Wilms’ tumor, they use imaging tests to look for signs of kidney tumors and any tumor cells that have spread beyond the kidneys. Wilms’ tumors that have spread within the abdomen can affect blood vessels, lymph nodes, and the liver, as well as tissue around the kidney. The most common place that Wilms’ tumor spreads outside the abdomen is the lungs.
To diagnose Wilms’ tumor, your child may receive a sonogram, which uses sound waves to produce images of the body, as well as chest x-rays and CT scans.
To keep cancerous cells from spilling out of the tumor, our doctors do not take a tissue sample to test for Wilms’ tumor. Instead, a surgeon removes the entire kidney along with the complete tumor to diagnose the disease. Our doctors can then look at the tumor cells with a microscope. If our doctors think your child may have Wilms’ tumor in both kidneys, each kidney will be looked at and treated separately.
In 90 percent of children with Wilms’ tumor, the cells appear relatively normal under the microscope and the disease can be more easily cured. When the cells appear deformed, they are more difficult to treat.
Because Wilms’ tumor is rare, most doctors have limited experience in caring for children who have it. However, doctors at Memorial Sloan Kettering have a long history of diagnosing and treating children with Wilms’ tumor. We treat up to ten new patients each year.
Wilms’ Tumor Staging
After our doctors diagnose a child with Wilms’ tumor, we find out how far the disease has spread. This process is known as staging. We do this using the staging system from the National Wilms’ Tumor Study Group. Staging is an important step that can help doctors find out what treatment is best for your child.
The cancer is only in the kidney and can be completely removed through surgery. About 40 percent of Wilms’ tumors are stage I tumors.
The cancer has spread to the areas around the kidney and can be completely removed through surgery. About 20 to 25 percent of Wilms’ tumors are stage II.
The cancer has spread to areas around the kidney, including blood vessels, lymph nodes, or other nearby organs, and cannot be completely removed through surgery. About 20 to 25 percent of Wilms’ tumors are stage III.
The cancer has spread beyond the area of the kidney into organs such as the lungs, liver, bone, or brain. About 10 percent of Wilms’ tumors are stage IV.
Tumors are found in both kidneys. Each kidney is staged separately. About 5 percent of Wilms’ tumors are stage V.