Wilms tumor, also called nephroblastoma, is a malignant (cancerous) tumor that originates in the cells of the kidney. It is the most common type of kidney cancer in childhood, affecting males and females equally and accounting for about 7 percent of all pediatric cancers.

Approximately 500 children in the United States are diagnosed with this tumor each year. Although the disease can occur at any age between infancy and 15 years, it is often detected in early childhood. The tumor can be very large and it may metastasize (spread) to other body tissues. The most common site of spread is the lungs, but lesions may also occur in the other kidney, the brain, and/or bones. In approximately 5 percent to 10 percent of children with Wilms tumor, both kidneys are involved.

Treatment strategies depend on a number of factors, including the stage of the disease and how aggressive the tumor appears under the microscope. However, surgical removal of the tumor is the cornerstone of therapy. Collaborative treatment strategies that involve pediatric surgeons, pediatric oncologists (cancer specialists), and radiation oncologists have resulted in treatments that cure the majority of patients diagnosed with Wilms tumor, although certain types of this cancer remain difficult to treat.

Cincinnati Children's Hospital Medical Center participates in the Children's Oncology Group, which is a multicenter research group of children's hospitals across the country. We follow the treatment protocols and guidelines that decades of research by such study groups have shown to be the most effective. New methods are continually being discovered to improve treatment and decrease side effects.