Wilms Tumor

A rare type of kidney cancer that primarily affects children is called Wilms tumor (also called nephroblastoma). It is the most common kidney cancer that happens in children. While it usually appears between 3 to 4 years, sometimes, it may occur after age 5, but less commonly. However, older children and even adults may also develop this form of kidney cancer.

Commonly, Wilms tumor impacts only one kidney, but it may affect both kidneys at the same time. In time, the diagnosis methods and treatments have greatly improved the prognosis for children with this cancer type. Generally, this condition is treatable, especially if it is found early.

Symptoms

People with Wilms tumor often experience different symptoms because it depends on the severity of the cancer, overall health, age, and other factors. Check below some symptoms that usually happen in people with this type of kidney cancer:

• A mass that forms in the stomach region and can be felt
• Stomach area swelling
• Abdominal (belly) pain
• Fever
• Blood in the urine
• Reduced red blood cell level (also called anemia)
• High blood pressure (hypertension)

If you notice that your child experiences any of the previous symptoms, immediately contact your healthcare professional.

Causes

Like any cancer type, it begins to develop when DNA changes occur in certain cells. In such cases, the DNA changes (mutations) happen in the kidney cells. In normal circumstances, DNA contains instructions that tell cells when to grow, multiply, and die. However, mutated DNA gives different instructions to the cells, which makes them grow and multiply without control. When abnormal cells become too numerous, they form a mass called a tumor. If you do not get treatment and the tumor becomes too large, it may break and spread to other body organs and structures (metastasize).

Healthcare providers do not know what exactly causes DNA changes that lead to Wilms tumor. In rare cases, certain abnormal genes may be passed from biological parents to their children and increase the risk of this cancer type.

Risk Factors

Physicians identified some factors that could elevate your risk of developing Wilms tumor. Examples include:

• Black people – The risk of developing Wilms tumor in North America and Europe in Black children is slightly higher than in other races. The lowest risk of developing this cancer type is in Asian American children.
• Family history of Wilms tumor – If you have a parent or sibling with this cancer type, your risk of developing it significantly increases.
• Aniridia – This is a congenital eye condition in which the iris (the colored part of the eye) does not form completely.
• Hemihypertrophy – In people with this condition, one side or part of the body is larger than the other side.
• WAGR syndrome – Generally, this syndrome includes aniridia, genital and urinary system issues, intellectual disabilities, and Wilms tumor.
• Denys-Drash syndrome – In such cases, the syndrome includes male pseudohermaphroditism and Wilms tumor. In children with pseudohermaphroditism, the male’s genitals are not clearly male.
• Beckwith-Wiedemann syndrome – This syndrome usually causes macrosomia in children. Moreover, it also causes a large tongue, large internal organs, and unusual ears.

How to Prevent Wilms Tumor?

Unfortunately, there is no way to prevent this cancer type. If your child has any of the conditions that increase the risk of Wilms tumor, regular checkups are recommended. While tests to diagnose Wilms’s tumor cannot prevent or treat the condition, they may help find it in its early stages.

Diagnosis

First, physicians will perform some examinations and ask some questions about your symptoms, medical and family history, and others. Thereafter, they will perform the following tests to confirm the condition and exclude others that cause similar symptoms. These include:

• A physical examination – During this procedure, physicians will check for abnormalities linked with Wilms tumor.
• Urine and blood tests – These tests are usually done to check kidney function.
• Imaging tests – The following tests are used to get detailed images of the kidneys. These tests may help identify the exact location and size of the tumor. Usually, physicians perform CT (computerized tomography) scans, MRI (magnetic resonance imaging) scans, or chest X-rays.

Additional Tests

Once you are diagnosed with Wilms tumor, healthcare professionals may perform some additional tests to determine the stage (extent) of the cancer. Staging the cancer helps make the best treatment plan for the patient. Check below what the Wilms tumor stages are in the U.S.:

• 1 – In such cases, the tumor is localized, meaning it has not spread to other body tissues or organs. Therefore, in people with the first cancer stage, doctors recommend surgery to remove the tumor. In most cases, this is the only treatment needed.
• 2 – In people with the second stage of the cancer, it spreads beyond the kidneys (such as to nearby fat or blood vessels).
• 3 – Those who experience this stage of cancer should know that the cancerous cells often spread to small organs (such as lymph nodes).
• 4 – Generally, this is end-stage of the cancer. Thus, the tumor breaks and spreads throughout the body negatively affecting multiple organs and structures. For example the lungs, liver, bones, brain, or others.
• 5 – In such cases, the cancer is found in both kidneys, and each one is staged itself.

Treatment

The most common treatments for children with Wilms tumor include surgery, chemotherapy, and radiation therapy.

Surgery

This procedure may confirm the condition and remove a part or all of the kidney. Moreover, surgeons may remove a small amount of healthy tissue around the tumor. Check below some surgery types often used to treat Wilms tumor:

• Partial nephrectomy – This involves the removal of the tumor and a small amount of kidney around it. Partial nephrectomy is often recommended for children with small tumors that develop only on one kidney.
• Radical nephrectomy – During this procedure, surgeons remove the kidney along with nearby lymph nodes, a part of the ureter, and the adrenal gland (in some cases). However, the remaining kidney works for both.
• The removal of a part or all kidneys – When cancer impacts both kidneys, doctors may remove as much cancer as possible. In some cases, surgeons may remove both kidneys, which means the child requires kidney dialysis or a kidney transplant.

Chemotherapy

This treatment involves strong medicines to destroy cancer cells throughout the body. While usually chemotherapy is given to patients intravenously (IV), a pill form is also available. Those who suffer from Wilms tumor often need more than one medicine to kill the cancer.

However, chemotherapy may cause adverse reactions including nausea, vomiting, appetite changes, hair loss, increased risk of infections, and others.

Sometimes, physicians recommend chemotherapy before surgery to shrink the tumor, making it easier to remove. When chemotherapy is prescribed after surgery, it is used to destroy cancer cells that may remain even after surgery.

Radiation Therapy

This therapy involves powerful energy beams to destroy cancerous cells. This energy usually comes from X-rays, protons, and other sources. During this treatment, the child will lie on a table while a machinery moves around him/her and delivers radiation exactly to the tumor. Sunburn-like skin irritation, tiredness, diarrhea, and nausea are the most common negative effects caused by this treatment.

Sometimes, radiation therapy is used to destroy cancer cells that remain after surgery, but it can also be used to control the cancer and prevent its spread to other body parts.

Frequently Asked Questions

What is the survival rate for Wilms tumor?

Generally, children with Wilms tumor who get treatment have a cure rate of 85% to 90%. However, when the cancer advances, the cure rate decreases. For instance, advanced tumors have a cure rate of nearly 70% to 80%, but it also depends on the cancer stage and if it has spread to other body parts or not.

What are the symptoms of a Wilms tumor?

Usually, people with this cancer type experience the following symptoms. For example:

• Fatigue (extreme tiredness)
• Hematuria (blood in the urine)
• Hypertension (high blood pressure)
• Swollen veins across the abdomen (belly)
• Constipation
• Pain in the abdominal area
• Fever

If any of the previous symptoms occur in your child, immediately visit a doctor.

What is the main cause of Wilms tumor?

While experts do not fully understand why it happens, they think genetic mutations (changes) that happen in the kidney cells cause the condition. Sometimes, DNA changes in the kidney cells that increase the risk of Wilms tumor are inherited from biological parents. Ask your healthcare provider if you have additional questions.