When Wilms' tumor is suspected, the standard procedure is to have a CT (computed tomography) scan, which examines the chest, abdomen, and pelvis for any signs of cancer. The abdomen is scanned to look for the tumor itself and for any signs of tumor cells having spread beyond their original source in the kidney to the kidney bed, lymph nodes, or to the liver, common sites of Wilms' tumor spread. And the chest is scanned to see if the tumor has spread to the lungs, the most common site for Wilms' tumor to spread.
CT scans may include the use of an intravenous dye containing iodine that produces clearer scans or images of the kidney, highlighting any possible tumor growth.
Once Wilms' tumor has been detected, if it is only on one side, the surgeon will remove the involved kidney with the tumor intact to verify the tumor's presence and to determine if it is of favorable or unfavorable histology (how the tumor's cells appear under microscopic inspection).
Wilms' tumor should not be biopsied because the procedure will contaminate the abdominal cavity with tumor cells and adversely affect the prognosis. In cases of favorable histology, which account for 95 percent of Wilms' tumor patients, the sample cells appear relatively normal, indicating a significantly greater chance of a cure. In cases of unfavorable histology, which account for five percent of Wilms' tumor incidence, the cells appear deformed and are more difficult to treat.
