Wilms Tumor
A Wilms’ tumour is a type of kidney cancer that usually affects young children. It is also known as a ‘Nephroblastoma’. Wilm’s tumour is the most common type of kidney cancer in children but is very rare.
The treatment for Wilms’ tumour usually includes surgery and may also include chemotherapy and radiotherapy. The outcome is usually very good and most children diagnosed with Wilms’ tumour will survive long-term.
A Wilm’s tumour is thought to come from very specialised cells that are involved in the development of kidneys. The specialised cells usually develop into normal kidney cells. If something goes wrong and some of the cells stayimmature then they grow out of control and develop into a Wilms’ tumour.
Wilms’ tumours are often divided into two main groups. The cells in each group look very different when looked at under a microscope. The appearance of cells under the microscope is called histology. The two types are:
Wilms’ tumour with favourable histology. Most Wilms’ tumours have favourable histology. This means that the cells have some similar features to normal kidney cells. Wilms’ tumours with favourable histology have an excellent chance of being cured with treatment.
Wilms’ tumour with unfavourable histology. Unfavourable histology means that the cells are completelyabnormal. This is called anaplasia. The cancer is less likely to be cured if there are lots of cells with anaplasia.
Wilms’ tumours usually only affect one kidney (unilateral). However, it can affect both kidneys (bilateral) in about 1 out of every 20 children who are diagnosed with Wilms’ tumour.
In most children, the causes of Wilms’ tumour are unknown. In about 1 in 100 children with Wilms’ tumour, another family member will also have Wilms’ tumour. This is because these children have inherited an abnormal gene from one of their parents. The abnormal gene increases the risk of Wilms’ tumour.
The most common symptom is a swelling in the abdomen which is gradually increasing in size and is felt by the parent one fine day. Other symptoms may include:
- Blood in urine.
- High temperature (fever).
- Loss of appetite with nausea and vomiting.
- Loss of weight.
A number investigation are done to diagnose a Wilms’ tumour and also for staging. An abdominal ultrasound scan is usually the first thing that is done. This is followed by an MRI scan and/or a CT scan of the abdomen and chest. These scans help to show exactly where the tumour is and whether it has spread to other parts of the body.Other tests will include blood tests to see how well the kidneys are working (kidney function tests) and to test for anaemia.
The stage of a cancer is used to describe the size of the cancer and whether it has spread to other parts of the body. This helps in deciding the treatment.
After examining the whole tumour under the microscope, Wilms’ tumours can be divided into a number of risk groups. The treatment following surgery will depend on these risk groups. The three main risk groups are known as low risk, intermediate risk and high risk.
Most Wilms’ tumours are in the ‘intermediate-risk’ group. So-called ‘low-risk’ tumours require less treatment after surgery than intermediate-risk tumours. ‘High-risk’ tumours need more treatment after surgery than ‘intermediate-risk’ tumours. The treatment will depend on a number of factors, including how the cells appear under the microscope (histology) and the stage of the tumour. Treatment usually includes an operation (surgery) and may also include chemotherapy and radiotherapy.
Surgery
All children with Wilms’ tumour will require surgery. Based on the imaging the surgeon decides for initial surgery or chemotherapy. The aim of surgery is to remove the whole of the tumour with the affected kidney (nephrectomy). However, in case of bilateral tumour or tumour in a solitary kidney, the tumour is removed leaving as much normal healthy kidney as possible.
Chemotherapy
Chemotherapygiven before surgery is known as neoadjuvant chemotherapy and is given to to shrink the size of the tumor and allow for complete surgical removal. Further chemotherapy may be needed after surgery, especially for Intermediate and ‘high-risk’ Wilms’ tumours, this is called adjuvant chemotherapy. Adjuvant chemotherapy helps to reduce the risk of the cancer coming back.
Radiotherapy
Not all children with Wilms’ tumour need radiotherapy. Radiotherapy may occasionally be used to shrink tumours that are too large to remove by surgery. Radiotherapy can also be used when tumours have spread elsewhere in the body.
Follow-up
After treatment for Wilms’ tumour your child will need regular check-ups to look for any return of cancer or for problems following treatment.
Outcome
The outcome for Wilms’ tumour is very good for all children, whatever their tumour stage. With treatment, 9 out of every 10 children diagnosed with Wilms’ tumour survive long-term. Most of the children with cancer that has spread to other parts of the body (metastatic disease) also survive long-term.
When one kidney is removed, the other will be able to work normally and can take over the work of the other kidney. Very few children with Wilms’ tumour have long-term kidney problems.