Wilms' Tumor

1 What is Wilms' Tumor?

Wilms' tumor, also known as nephroblastoma, is a type of kidney cancer found in children. Though rare, it is the most common cancer of the kidneys in children. Usually, it affects children ages 3 to 4 but is less likely to occur after 5. It commonly affects a single kidney, though it can affect both kidneys at the same time. With advancement of diagnostic and treatment techniques, prognosis is getting better.

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2 Symptoms

No signs and symptoms of Wilms' tumor may be noticed or if any, they include: 

  • Swelling of abdomen 
  • A palpable abdominal mass 
  • Abdominal pain 
  • Fever 
  • Blood in the urine 

When to see a doctor? 

Visit your child's doctor if your child has any signs or symptoms. In most cases, the signs and symptoms are caused by other conditions.

3 Causes

The cause of Wilms' tumor is unknown. Normal cells in kidney turn into cancer cells due to changes in the DNA (DNA mutations). DNA mutations cause an “out-of-control” cell growth and multiplication leading to accumulation of abnormal cells (tumor). These cancer cells can affect surrounding tissues or dislodge from site of origin and spread to other body parts (metastasis).

In most cases, it is less likely that a genetic mutation passed from parents to the children causes Wilms’ tumor.

4 Making a Diagnosis

If you are worried due to signs and symptoms of Wilms' tumor in your children, you can visit your doctor or your child's pediatrician to receive a diagnosis. If diagnosis is confirmed, you may see a specialist in cancer (oncologist) or a surgery specialist in kidney disorders (urologist). 

How to prepare yourself for the visit?

Getting prepared for the visit can optimize the therapy and help make the visit more fruitful.

List out all the symptoms.

Write down your key medical information. 

Write down the names of all your medications, vitamins or supplements. 

Ask a friend or a family member to accompany you during the visit.

Make a list of the questions to ask your doctor. Some typical questions can be: 

  • What could be the most probable cause of my child's symptoms? 
  • What kinds of tests are needed? 
  • Can you tell me about the stage of my child's cancer? 
  • What are the treatment options and side effects of each option? 
  • Do you suggest any treatment alternatives? 
  • Does my child need to restrict any activity or change his or her diet during treatment? 
  • What are the chances of recovery? 
  • Can this cancer recur? 

What your doctor wants to know?

A clear talk with your doctor can optimize the therapy and improve the outcomes. Prepare yourself to answer some essential questions from your doctor. Your doctor might ask you typical questions like: 

  • When was the first time you noticed your child's symptoms? 
  • Does anyone in your child’s family have cancers like childhood cancer or birth defects such as those of the genitals or urinary tract?

Diagnostic tests for Wilms' tumor

  • A physical examination: The doctor has a thorough study of your child’s signs and symptoms that could possibly be associated with Wilms' tumor? 
  • Blood and urine tests: Blood tests are performed not to detect Wilms' tumor, but to determine overall health status of your child. 
  • Imaging tests: Imaging tests like ultrasound, computerized tomography (CT) and magnetic resonance imaging (MRI) can be done to detect kidney tumor, if any. 
  • Surgery: Surgery may be used for both diagnosis and treatment of the cancer. It involves surgical removal of the tumor or the entire affected kidney to determine if the tumor is cancerous. The tissue obtained from surgery is further analyzed in the lab to look for cancer and its types. 


Staging a cancer is based on the extent of cancer. Staging is important to determine appropriate treatment and hence its outcome. Staging may be done by a chest X-ray, chest CT scan and bone scan to

The stages of Wilms' tumor are: 

  • Stage I: Cancer affects only one kidney and complete surgical removal is possible.
  • Stage II: Cancer has extended beyond one kidney to nearby tissues and structures but and complete surgical removal is possible. 
  • Stage III: The cancer has spread to adjacent lymph nodes or other structures inside the abdomen, and complete surgical removal is not possible. 
  • Stage IV: Cancer has extended to the structures that are far from the kidney, such as the lungs, liver, bones or brain. 
  • Stage V: Both the kidney are affected.

5 Treatment

Surgery and chemotherapy form the mainstay of Wilms' tumor treatment. As the cancer is rare, you may not find treatment facilities in every hospital. You may have to look for treatment at a children's cancer center that has been treating this type of cancer. 

Treatments include:

  • Surgery: Surgery is the most important treatment option and it may be carried out to remove a portion of or an entire kidney (nephrectomy) or to confirm the diagnosis. Surgery options include: 
    • Partial nephrectomy: It involves surgical removal of the tumor and nearby tissues in case only one kidney is working or the cancer is limited to a very small area. 
    • Radical nephrectomy: It involves surgical removal of the entire kidney, adjacent tissues including the ureter and adrenal gland, and less often nearby lymph node. Healthy kidney can upgrade to compensate for the loss. 
  • Removing all or part of both kidneys: This choice is made when both kidneys are affected by the cancer. Upon the removal of both kidneys, your child needs either kidney dialysis or a kidney transplant.
  • Chemotherapy: It uses chemical drugs to kill cancer cells throughout the body which may be given orally or through a vein. Your child can experience side effects such as nausea, vomiting, loss of appetite, loss of hair and frequent infections. If used before surgery, chemotherapy causes tumors to shrink thus facilitating removal. It can also be used after surgery to destroy any cancer cells that have survived the surgery. Children with advanced surgery may also be prescribed chemotherapy. If both kidneys are affected, chemotherapy is given prior to surgery. 
  • Radiation therapy: It uses ionizing radiations such as X-rays to kill cancer cells. Your child may experience side effects like nausea, diarrhea, fatigue and sunburn-like skin irritation. If some cells remain even after surgery, radiation can be used to destroy them. Radiation can also kill the cancer cells that have spread to other parts of the body.
  • Clinical trials: These are the experiments performed to demonstrate the benefits of new treatment methods. Clinical trials do not guarantee a cure. Discuss with your child’s doctor before participating in a clinical trial. 

6 Prevention

Unfortunately, Wilms' tumor is not preventable. If your child’s doctor assumes greater risk for your child, s/he may recommend regular kidney screenings to detect kidney abnormalities.

Remember that screening is not a preventive measure, rather it may facilitate early detection which in turn increases likelihood of a better treatment outcome.

7 Lifestyle and Coping

Here are some suggestions to help you cope with Wilms' tumor:

  • Stay close: Support your child during a test or treatment, whenever possible. Show affection and care whenever possible. 
  • Let your child play: If your child is in hospital for treatment, allow him/her some time daily to indulge in some play. A playroom inside hospital can be a great place to unwind. You may consult a recreational therapist if your child is bound to bed. 
  • Let your child rest: You may allow some time for play if your child is well enough. Cancer treatments can cause tiredness, so allow your some quite time to rest. 
  • Record your child's condition at home: You can keep a record of body temperature, energy level, sleeping patterns, eating habits, drugs administered and their side effects. This information may be useful to your child’s doctor. 
  • Plan a healthy diet for your child: You can plan a healthy diet after consulting with your child's doctor. Cancer treatments can cause problems with eating like loss of appetite. Make sure your child gets all the essential nutrients. 
  • Encourage good oral hygiene for your child: If your child develops sores, a mouth rinse can provide relief. For cracked lips, you can use a lip balm. Suggest proper dental care measures before the treatment. 
  • Talk to the doctor before any vaccinations.
  • Talk about the illness with your other children: Inform them about what changes they might observe in their sibling, such as hair loss and weakness
  • Join a support group where you can share your thoughts, experience and expectations with parents of children with cancer. Talk to your child's doctor if you are interested to join a support group.

8 Risks and Complications

There are several risks and complications associated with Wilms' tumor, which include:

  • Race: Black children are at a greater risk than those of other races. 
  • Family history: History of Wilms' tumor in someone close to your child increases the risk.

Wilms' tumor is more common in children with certain congenital abnormalities like: 

  • Aniridia, a condition characterized by partial or absent iris.
  • Hemihypertrophy, a condition in which one side of the body is significantly larger than the other. 
  • Undescended testicles: A condition in which testicle/s fail to move down into the scrotum (cryptorchidism). 
  • Hypospadias. The urinary (urethral) opening on the underside of the penis. 

Wilms' tumor can occur as part of:

  • WAGR, a rare genetic syndrome which includes: W- Wilms’ tumor, A- Aniridia, G- Genital abnormalities and R- Retardation. 
  • Denys-Drash syndrome: a rare genetic syndrome that includes Wilms' tumor, kidney disease and male pseudohermaphroditism.
  • Beckwith-Wiedemann syndrome: an overgrowth syndrome characterized by abdominal organs that protrude into the base of the umbilical cord, an enlarged tongue (macroglossia) and enlarged internal organs.  

9 Related Clinical Trials