What is Wilms' tumour?

Nephroblastoma or Wilms’ tumour is one of the most common malignant tumours in children. It is associated with an abnormal proliferation of cells similar to embryonic kidney cells (metanephric), which is where the term embryonal tumour comes from. 

It normally occurs in childhood. Around 80 per cent of tumours appear in children under five years old, but they are not common in children over 15 or newborns.

What are the symptoms?

There are many symptoms associated with Wilms' tumour. These include:

• Palpable abdominal mass that is normally unilateral and painless.
• A (normally) vague abdominal pain. This tends to happen in about 30 per cent of cases.
• High temperature.
• Constipation, nausea, and vomiting.
• Blood in urine (haematuria).
• Arterial hypertension.

What causes it?  

The exact cause for a nephroblastoma or Wilms’ tumour in children is unknown. It is sometimes linked to an absence of the iris (aniridia), which is caused by a birth defect. It is more common in siblings and twins.

Other congenital defects linked to cancer include urinary tract issues and hemihypertrophy, where one side of the body is larger than the other.   

How can it be prevented, and how is it diagnosed?

There isn’t a known way to prevent nephroblastoma from happening. Some tests include an ultrasound of the kidneys, for children with a higher risk of getting the tumour, for example due to having some of the associated symptoms. These tests are useful to detect the disease in its early stages.

How is Wilms' tumour treated?  

There are different kinds of treatment available for patients with this condition. Some cancer treatments can cause side effects months or years after treatment.

There are five kinds of standard treatment: 

• Surgery: nephrectomy or partial nephrectomy
• Internal or external radiotherapy
• Chemotherapy
• High dose chemotherapy with stem cell rescue
• Biological therapy: monoclonal antibodies, kinase inhibitors, inhibitors of histone methyltransferase.