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Wilms tumor

Every year, approximately 35 children in the Netherlands are diagnosed with a kidney tumor. Most of those children are not yet 5 years old. Kidney tumors are just as common in girls as they are in boys. Wilms tumors can already develop in the womb.

The brochure Kidney tumors contains comprehensive information on this disease. Please note this brochure is currently only available in Dutch. The most important information is provided below.


Kidney tumors are caused by a developmental error in a (progenitor) cell of the supporting cells. Sometimes a piece of DNA is damaged or a part of a chromosome is missing. It is not known exactly what causes this error. The tumor can already develop in the womb.


Kidney tumors often do not cause symptoms for quite some time. A swollen abdomen is usually the first indication that something is wrong. Some children have blood in their urine or they have a stomach ache.

How are Wilms tumors diagnosed?

In addition to urinalysis, an ultrasound of the abdomen is performed as well as various scans.


Children with a Wilms tumor are treated according to a protocol drawn up by national and international experts. The treatment depends on the stage of the tumor. A metastasized tumor, or a tumor in two kidneys, requires more intensive treatment than a tumor in one location. Treatment usually consists of 4-6 weeks of chemotherapy, surgery and follow-up chemotherapy treatment. Children under six months old are usually operated immediately.

The operation is followed by another round of chemotherapy. Some children also receive radiotherapy treatment.

Chance of recovery

If a Wilms tumor is detected early and has not spread, there is an 80% to 90% chance of recovery. Even if there are metastases, the chances are favorable (75%). It is difficult to make predictions. Don't be influenced too much by statistics. Every child and every situation is unique.


Children with a Wilms tumor are treated in the solid tumors department.

Phone 088-9727272