Wilms' Tumor and Other Childh... Health Article

Description

What is Wilms’ tumor?

Wilms’ tumor is a disease in which cancer (malignant) cells are found in certain parts of the kidney. The kidneys are a “matched” pair of organs found on either side of the backbone. The kidneys are shaped like a kidney bean. Inside each kidney are tiny tubes that filter and clean the blood, taking out unneeded products, and making urine. The urine made by the kidneys passes through a tube called a ureter into the bladder where it is held until it is passed from the body.

Wilms’ tumor is curable in the majority of affected children. If your child has symptoms, your child’s doctor will usually feel your child's abdomen for lumps and run blood and urine tests. The doctor may order a special x-ray called an intravenous pyelogram. During this test, a dye containing iodine is injected into your child's bloodstream. This allows your child's doctor to see the kidney more clearly on the x-ray. Your child's doctor may also do an ultrasound, which uses sound waves to make a picture, or a special x-ray called a computed tomographic scan to look for lumps in the kidney. A special scan called magnetic resonance imaging, which uses magnetic waves to make a picture, may also be done. Chest and bone x-rays may also be taken.

If abnormaltissue is found, your child's doctor will need to cut out a small piece and look at it under the microscope to see if there are any cancer cells. This is called a biopsy.

Your child's chance of recovery (prognosis) and choice of treatment depend on the stage of your child's cancer (whether it is just in the kidney only or has spread to other places in the body), how the cancer cells look under a microscope (histology), and your child's age and general health.

What Are Other Childhood Kidney Tumors?

Clear cell sarcoma of the kidney, rhabdoid tumor of the kidney, and neuroepithelial tumor of the kidney are childhood kidney tumors unrelated to Wilms' tumor. The treatment of these tumors is different from that of Wilms' tumor but because of their location near the kidneys, they have been treated on clinical trials developed by the National Wilms' Tumor Study Group.

Stage Explanation

Stages of Wilms' tumor

Once Wilms' tumor has been found, more tests will be done to find out if cancercells have spread from the kidney to other parts of the body. This is called staging. Your child's doctor needs to know the stage of the disease to plan treatment. For Wilms' tumors, the stage is based on the amount of tumor that remains after the patient has had surgery to look at or remove the tumor. The following stages are used for Wilms' tumor:

Stage I

The tumor was completely removed by surgery and all of the following are true:

• Cancer was found only in the kidney and did not spread to blood vessels of the kidney.

• The outer layer of the kidney did not break open.

• The tumor did not break open.

• A biopsy of the tumor was not done.

• No cancer cells are found at the edges of the area where the tumor was removed.

Stage II

Cancer has spread deeper into other parts of the kidney and to nearby blood vessels, but was completely removed by surgery. No cancer cells are found at the edges of the area where the tumor was removed.

Stage III

Cancer remains in the abdomen after surgery to remove the tumor but no cancer remains in or on the blood vessels. Any 1 of the following may be true:

• Cancer has spread to lymph nodes in the abdomen or pelvis (the part of the body between the hips).

• Cancer has spread through the peritoneum (the layer of tissue that lines the abdominal cavity and covers most organs in the abdomen) or is found on the surface of the peritoneum.

• Cancer cells are found at the edges of the area where the tumor was removed.

• Cancer has spread to nearby tissues, where it cannot be completely removed by surgery.

• Cancer cells are found in the abdominal cavity (tumor cells spilled there before or during surgery).

• A biopsy of the tumor was done before surgery to remove it.

• The tumor was removed in more than 1 piece.

Stage IV

Cancer has spread through the blood to the lungs, liver, bone, or brain, or to lymph nodes outside of the abdomen and pelvis.

Stage V

Cancercells are found in both kidneys when the disease is first diagnosed. The cancer in each kidney will be staged as I, II, III, or IV.

Recurrent

Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may come back where it started or in another part of the body.

Favorable and Anaplastic Histology

In Wilms’ tumor, how the cancercells look under a microscope (histology) is also very important for describing stage and determining treatment options. The cancer cells can be of favorable histology or anaplastic histology. Anaplastic means the cancer cells divide rapidly and look very different from normal cells. Anaplastic tumors may be focal (in one area) or diffuse (spread widely throughout an area).