Diagnosis

To diagnose Wilms' tumor, your child's doctor may recommend:

• A physical exam. The doctor will look for possible signs of Wilms' tumor.
• Blood and urine tests. These lab tests can't detect Wilms' tumor, but they can indicate how well the kidneys are working and uncover certain kidney problems or low blood counts.
• Imaging tests. Tests that create images of the kidneys help the doctor determine whether your child has a kidney tumor. Imaging tests may include an ultrasound, computerized tomography (CT) or magnetic resonance imaging (MRI).

Staging

Once your child's doctor diagnoses Wilms' tumor, he or she works to determine the extent (stage) of the cancer. The doctor may recommend a chest X-ray or chest CT scan and bone scan to determine whether the cancer has spread beyond the kidneys.

The doctor assigns a stage to the cancer, which helps determine the treatment options. In the United States, guidelines developed through the National Wilms Tumor Study of the Children's Oncology Group include these five stages:

• Stage I. The cancer is found only in one kidney, is completely contained within the kidney, and can be completely removed with surgery.
• Stage II. The cancer has spread to the tissues and structures beyond the affected kidney, such as nearby fat or blood vessels, but it can still be completely removed by surgery.
• Stage III. The cancer has spread beyond the kidney area to nearby lymph nodes or other structures within the abdomen, the tumor may spill within the abdomen before or during surgery, or it may not be completely removed by surgery.
• Stage IV. The cancer has spread outside the kidney to distant structures, such as the lungs, liver, bones or brain.
• Stage V. Cancer cells are found in both kidneys (bilateral tumors).