Staging, risk groups and treatment plans for Wilms tumour
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 risk groups:
- low
- medium
- high
Doctors decide on a risk group based on what the 
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. Your child won’t need any treatment after surgery if they have a low risk tumour.
If your child has a medium risk tumour, they will have a further 4 weeks of chemotherapy. For a high risk Wilms tumour, they’ll have 27 weeks of chemotherapy. Your child also usually has another chemotherapy drug called doxorubicin.
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. The cancer was completely removed during surgery.
Treatment
Treatment for low or medium 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. This usually lasts for 27 weeks. Some medium risk Wilms tumours will also have doxorubicin chemotherapy.
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. They may or may not have radiotherapy. This depends on what the cells look like under a microscope.
High risk tumours use different chemotherapy drugs. Your child will alternate between each . The courses are:
- cyclophosphamide and doxorubicin
- etoposide and carboplatin
Stage 3
Stage 3 means one of the following. The tumour has
- not been completely removed during surgery
- spread to the
lymph nodes in the tummy area (abdomen) - burst, before or during, the surgery
- spread to the lining of abdomen (the peritoneum),
ureter or blood vessels
If your child needed a sample of tissue (biopsy) before starting treatment with chemotherapy, this could mean that the tumour becomes stage 3. Having a biopsy taken through an operation is called an open biopsy.
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. For low and medium risk tumours they have 27 weeks of chemotherapy. For high risk, they have 34 weeks of chemotherapy.
Your child usually also has radiotherapy for medium or high risk tumours.
If your child has a high risk tumour they’ll alternate between the following chemotherapy drugs. The courses are:
- cyclophosphamide and doxorubicin
- etoposide and carboplatin
Stage 4
Stage 4 means that the tumour has spread to a distant part of the body. This is most commonly the lungs. About 10 to 20 children out of 100 (10 to 20%) have cancer that has spread to the lungs at diagnosis. But Wilms tumours can also spread to other parts of the body such as the liver, bones, 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 more 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 more chemotherapy after surgery. They might also have radiotherapy.
