The stage of a cancer tells you the size and whether it has spread. Knowing the stage can help your doctor decide which treatment your child needs.

The tests and scans your child had to diagnose the cancer give some information about the stage. It is not usually possible to be certain about the stage of a Wilms’ tumour until after surgery.

Doctors use a number system to stage Wilms’ tumours. The International Society of Paediatric Oncology (SIOP) has designed the staging system for the UK and the rest of Europe.

Outside of Europe, the Children’s Oncology Group (COG) uses a similar but slightly different staging system.

Risk groups

Doctors group Wilms’ tumours in terms of risk of the cancer coming back after treatment. There are 3 groups low, medium or high risk. Doctors decide on a risk group based on what the pathologist sees down the microscope when the tumour is looked at after surgery.

Stage 1

Stage 1 means the tumour is only affecting the kidney. The tumour has not spread and it was completely removed during surgery.

Treatment

Treatment for stage 1 Wilms’ tumour is usually chemotherapy for 4 weeks. Then, surgery to remove the kidney. After surgery, your child usually has more chemotherapy if they have an intermediate or high risk Wilms’ tumour. They have no further treatment if they have a low risk tumour.

Stage 2

Stage 2 means the tumour has spread beyond the kidney to the nearby structures. There are no cancer cells in distant organs, such as the lungs. It was completely removed during surgery.

Treatment

Treatment for low or intermediate risk stage 2 Wilms’ tumour is usually chemotherapy for 4 weeks. Then, surgery to remove the tumour. 

After surgery, your child usually has more chemotherapy. How long they have chemotherapy depends on their risk. For a:

• low risk tumour they have chemotherapy for 4 weeks
• intermediate risk tumour they have chemotherapy for 27 weeks

 Some children also have radiotherapy. This is because the cells look very large and not like normal kidney cells under a microscope. 

Treatment for high risk stage 2 Wilms’ tumour is usually chemotherapy for 4 weeks. Then, surgery to remove the kidney. After surgery, your child usually has:

• more intensive chemotherapy for 34 weeks
• radiotherapy – for intermediate and high risk tumours

Stage 3

Stage 3 means the tumour has either:

• not been completely removed during surgery
• spread to the lymph nodes in the tummy area (abdomen)
• burst, before or during, the surgery

Rarely, your child’s surgeon needs to take a sample of tissue (open biopsy) before chemotherapy. This is usually because they can’t remove the tumour. After an open biopsy, these tumours are classed as a stage 3 Wilms’ tumour.

Treatment

Treatment for stage 3 Wilms’ tumour is usually chemotherapy for 4 weeks. Then, surgery to remove the kidney. After surgery your child will usually have:

• chemotherapy - how long this is for depends on your child’s risk group
• radiotherapy

Stage 4

Stage 4 means that the tumour has spread to a distant part of the body. This is most commonly the lungs, but might be the liver, bone, brain or lymph nodes in an area outside the tummy (abdominal) or pelvic area.

Treatment

Treatment for stage 4 Wilms’ tumour is usually chemotherapy for 6 weeks, then surgery to remove the kidney. After surgery, your child is likely to have chemotherapy and may have radiotherapy. The exact treatment schedule depends on:

• your child’s risk group
• how well treatment is working

Stage 5

Stage 5 means there are tumours in both kidneys. This is called bilateral Wilms’ tumour. Doctors stage each of the tumours separately.

Treatment

Treatment is usually chemotherapy first. Then, surgery to remove as much of the cancer as possible from each kidney. Your child’s surgeon will aim to keep as much healthy kidney tissue as possible.

It’s likely your child will have chemotherapy after surgery. They might also have radiotherapy.

Treatment