What Is Wilms Tumor?

Overview

Wilms’ tumour, also known as nephroblastoma, is a rare type of paediatric kidney cancer. It typically develops in children between the ages of 2-5.¹ Symptoms associated with the disease can range from an abdominal mass, weight loss and blood in the urine amongst others.² However, it can also be asymptomatic. It is treated by surgery, chemotherapy and sometimes radiation therapy. This cancer typically has high survival rates.³ However, it is worth noting, the outcome is dependent on several factors including the tumour stage, the spread of the cancer and the age of the child individual diagnosed.

Causes of Wilms' tumor

The exact cause of Wilms’ tumour is unknown. However, there is some research suggesting that both environmental and genetic factors may contribute to the development of Wilms’ tumour. 

According to the NHS website 1 out of 100 people that have Wilms’ tumour will have another family member that also has this form of kidney cancer. This suggests a genetic predisposition to the condition can contribute to the development of Wilms’ tumour. 

In addition, it has also been suggested maternal exposure to certain toxins or chemicals during pregnancy or direct exposure to certain toxins or chemicals during early childhood may be a possible risk factor for the disease. However, further research is required to establish these possible links.^{4, 5}

Although the above might increase the likelihood of Wilms’ tumour development, it does not mean you will develop the disease. Wilms’ tunour is a rare condition, and therefore, even with risk factors for the condition most people will not develop the illness. 

Signs and symptoms of Wilms' tumor

The signs and sypmtoms of Wilms' tumour may vary from child to child. In some children Wilms’ tumour is asymptomatic, whilst in other children it may cause several different symptoms. When the tumour is asymptomatic it is usually detected as part of a routine check-up. Symptoms that can be experienced by a child with Wilms’ tumour according to the mayoclinic include:

• Abdominal swelling or an abdominal mass
• Abdominal pain
• Blood in urine
• Fever
• High blood pressure
• Anaemia
• Loss of appetite

Management and treatment for Wilms' tumor

A multidisciplinary approach is normally used in the treatment and management of Wilms’ tumour. It usually involves a combination of surgery and chemotherapy, and in some cases radiotherapy.³ Your childs doctor will consider factors such as the tumour stage, the childs age, and the presence of any genetic syndromes when determining the exact treatment plan for the individual case of Wilms’ tumour. 

The majority of patients, with the exception of those under 6 months will have chemotherapy prior to surgery. Chemotherapy refers to the use of drugs that kill cancer cells. These anti-cancer drugs are usually given via an injection or a drip into a vein. Additional chemotherapy following surgery may be required.⁶ This is dependant on additional testing carried out on the cancer following surgery.

Every child with Wilms’ tumour will require surgery. The aim of the surgery is to remove the tumour and the affected kidney whilst preserving as much healthy kidney tissue as possible. In cases of bilateral Wilms’ tumour, in which the cancer affects both kindeys, surgery to both kidneys is usually performed. Following surgery, the cancerous tissue that is removed is examined by a pathologist and the results of this examination will determine if there are any further treatment courses required.⁷

In certain cases, radiotherapy may also be recommended. This is used to target any remaining cancer cells and reduce the risk of this type of kidney cancer recurring. Radiotherapy uses high energy X-rays to destroy cancer cells whilst doing as little damage to normal healthy cells.⁷

The 5-year survival rate for this cancer type is approximately 92%.⁸

Diagnosis

Wilms’ tumour is diagnosed through a combination of a medical history evaluation, a physical examination, imaging tests and possibly a biopsy. 

Your doctor will first ask about your childs medical history, this should address any symptoms or concerns you have. Then they will perform a physical exam on your child, this will focus on their abdomen region to check for the presence of a mass or swelling.

Imaging tests including an ultrasound, MRI and CT scan can be used to visualise the tumour. This helps medical professionals deternime its characteristics. The characteristics that can be determined through imaging tests include the tumour size, its spread and its location. 

In some cases a biopsy might be performed to confirm the diagnosis of Wilms’ tumour. However, Wilms’ tumour can normally be diagnosed with just imaging tests. Biopsies are usually avoided to avoid the risk of spreading cancer cells.

Following a diagnosis of Wilms' tumour, the cancer will then be assigned a stage by a group of specialists. This group normally includes paediatric oncologists, radiologists, pathologists, and surgeons.³ The stage of the cancer helps determine the most appropriate treatment plan for your child.

Risk factors

There are a few risk factors that have been identified for Wilms’ tumour. Having one or even all these risk factors does not mean your child will develop Wilms’ tumour, in fact most cases of Wilms’ tumour occur without any known risk factors. Recognised risk factors include:

• Genetic syndromes including WAGR syndrome⁹ and Beckwith-Wiedemann¹⁰
• A family history¹⁰
• Gender: girls are slightly more likely to develop Wilms’ tumour
• Age: highest incidence rates are in those 2-5 years old
• Race: it is more common in children of African descent 
• Some birth defects are associated with Wilms’ tumour⁸

FAQs

Can Wilms' tumor be prevented

Currently, there are no known prevention methods for Wilms’ tumour. However, early detection of the disease and a prompt medical intervention can improve the prognisis and overall outcome of the kidney cancer. 

How common is Wilms' tumor

Wilms’ tumour is a rare paediatric cancer. Approximately 650 new cases of Wilms’ tumour are diagnosed in the United States each year.⁸

When should I see a doctor

If you are concerned that your child is presenting any signs or symptoms listed above for Wilms’ tumour you should contact a healthcare professional promptly. Early detection and intervention greatly improve the overall prognosis of the disease. 

Summary

To summarise, Wilms’ tumour, also known as nephroblastoma, is a paediatric kidney cancer. It is a rare condition with a generally good prognosis. It is most commonly diagnosed in those aged 2-5 years old. The symptoms can vary case by case, but if you do suspect you child might have Wilms’ tumour you should contact a medical professional promptly.