Wilms’ tumour
A Wilms’ tumour is a malignant (cancerous) tumour that develops in the kidney from specialised cells called nephroblasts. It is also called a nephroblastoma. Usually it occurs in only one kidney (unilateral), although occasionally there may be tumours in both kidneys (bilateral). Sometimes the tumour can spread (metastasise) to other parts of the body, such as the lungs or liver.
Approximately one in ten thousand children get Wilms’ tumour. About 70 children develop Wilms’ tumour in the UK each year. It most often affects children below the age of five and is slightly more common in girls than boys.
In most cases there is no known cause for Wilms’ tumour, although a small number of children have a genetic tendency. This is usually obvious, either because other members of the family have had Wilms’ tumour or because the child has certain growth or development problems that have been present from birth. However, for the majority of children with Wilms’ tumour, there is no genetic tendency, nor is there any increased risk in brothers or sisters.
Signs and symptoms
The most common symptom of Wilms’ tumour is swelling of the abdomen (tummy). This is usually painless. Other symptoms may include:
- nausea and vomiting
- poor appetite
- weight loss
- abdominal pain
- fever
- red urine due to blood in the urine
- high blood pressure.
Tests and investigations
Your doctors will need to carry out some tests to find out as much as possible about the type, position and size of the tumour. The tests will include:
- urine and blood samples to show how well the kidneys are working as well as some other information about general health
- chest X-ray to show if the tumour has spread to the lungs
- ultrasound scan to show the position and size of the tumour
- CT scan to give more detailed information about the tumour and show if it has spread
- biopsy, a small operation, usually carried out under general anaesthetic, in which a surgeon removes a small piece of tissue from the kidney to help make a diagnosis.
Staging
The tumour stage is a measure of how far the tumour has spread beyond the kidney. This can only be measured accurately after surgery to remove the affected kidney. Knowing the particular type and stage of the cancer helps the doctors decide on the most appropriate treatment.
The following describes the staging system used for Wilms’ tumours:
- Stage I: the tumour is confined to the kidney and is completely removed at the time of surgery
- Stage II: the tumour has broken through the kidney lining but is still completely removed at the time of surgery
- Stage III: some of the tumour is left behind at the time of surgery, either because the tumour breaks or because complete surgical removal is not possible
- Stage IV: the tumour has spread to other parts of the body, usually the lungs or lymph nodes (glands)
- Stage V: there is tumour in both kidneys (bilateral disease).