Wilms’ tumor, also known as nephroblastoma, is a rare form of kidney cancer that affects young children. About 500 cases are diagnosed each year, generally at two to five years of age. If diagnosed and treated early, up to 95% of Wilms' tumor cases are curable.
The stage is set for Wilms’ tumor in the womb. As kidney cells mature in the fetus, they become specialized and form different regions of the kidney. Some of these cells are still immature at birth and continue to develop over the first three or four years of life. In Wilms’ tumor, however, the cells remain immature and begin to reproduce rapidly, forming a mass that can grow quite large before it produces any symptoms.
The most common and noticeable symptom of Wilms' tumor is a hard lump or mass in the stomach area, easily felt through the skin. Less frequent symptoms include:
In many cases, parents are the ones who discover the tumor when it grows large enough to be seen or felt. Imaging techniques such as MRI, CT scans, ultrasound or chest X-rays may be used to confirm the doctor's suspicions, but very few of them are found in early stages when they are smaller. Other tests may be used to see if the tumor has spread or to determine the best treatment approach.
Wilms' tumor is usually treated with a combination of surgery and chemotherapy. This disease generally affects only one kidney. The cancerous organ is removed along with the adrenal glands and a small margin of surrounding tissue, in a surgical procedure called a nephrectomy. If the tumor is very large or has spread to other organs and tissues, chemotherapy or radiation therapy may be used to shrink the tumor before attempting surgery. Radiation is also used as a primary treatment in some advanced cases.