Wilms' Tumor

Note: This section has health/medical information. It was not written by a health care professional. The medical references are:

NCI web site sections on Wilms' Tumor , accessed 2007
Childhood Cancer: A Parents Guide to Solid Tumor Cancers, 2th ed., by Honna Janes-Hodder and Nancy Keene, 2002

Wilms tumor is a cancerous tumor on the kidney. Also called nephroblastoma, it is the most common form of childhood kidney cancer, although it is not related to adult kidney cancer. The kidneys are located at the back of the abdominal cavity, to the left and to the right of the backbone. They serve to filter the blood and rid the body of excess water, salt, and waste products.

What is Wilms' Tumor?

The kidney develops while the baby is still in the womb. At birth, some kidney cells have not yet differentiated fully into the various types of cells that make up a mature kidney. Generally, by the time a child is 3 or 4 years old all cells have properly matured. But sometimes some of these immature cells start to grow out of control. The result is a mass of wildly growing primitive, small cells, called Wilms tumor.

Usually Wilms' tumors are one mass in one kidney, but sometimes they are found in both kidneys, or bilateral. Usually Wilms' tumors are not diagnosed until they have become quite large; most are found before they metastasize.

Certain birth defects, or syndromes, are associated with 15% of Wilms' tumor cases, especially WAGR, Beckwith-Wiedemann syndrome, and Denys-Drash syndrome. Also, 1-2% of Wilms' patients have a relative with the same type of tumor. Rare kidney tumors (not Wilms') are: clear cell sarcoma of the kidney (CCSK) and malignant rhabdoid tumor of the kidney.

Treatment

Wilms is best treated when it is found early, before it has spread to other areas of the body. Almost half of Wilms' tumors are found before they reach stage II, which means that they are limited to the kidney and are completely excised.

Staging information on cancer.gov

Treatment plans depend both on the stage of the tumor and whether they have a favorable or an unfavorable histology:

favorable Cells lack anaplasia; 95% of Wilms' tumors fall into this category.
unfavorable Cells have anaplasia, defined as nuclei which are distorted very large.

Treatment for Wilms includes surgery, chemotherapy, and possibly radiation, depending on how far the cancer has spread.

Search form for clinical trials on the cancer.gov site

Statistics

It accounts for 6-7% of childhood cancer cases.
Usually occur in children up to age 8; rare in adults.
Average age of patients with Wilms tumor is 2-3
75% occur before age 5
It occurs in about 8 in 1 million children under age 14
2-5% are in both kidneys
5 year survival rate is 90-93%

Ped-Onc Resources for Wilms

The following ped-onc resource lists have appropriate sections for parents of children with Wilms:

childhood cancer e-mail lists - the ACOR Wilms tumor list (Wilms-kids) and the general childhood cancer list, ped-onc, are both appropriate
support organizations
books and printed materials - especially the book Childhood Cancer, A Parents's Guide to Solid Tumor Cancers, by Honna Janes-Hodder and Nancy Keene.
young people with Wilms tumor - personal home pages

Links to More Information

The following web sites provide good, general information on Wilms.

cancer.gov main page for Wilms tumor
National Wilms Tumor Study Group
Wilms Tumour dot com A great patient-generated web site.

General Disclaimer

These pages are intended for informational purposes only and are not intended to render medical advice. The information provided on Ped Onc Resource Center should not be used for diagnosing or treating a health problem or a disease. It is not a substitute for professional care. If you suspect your child has a health problem, you should consult your health care provider.

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