Wilms Tumor - Early Signs, Risk Factors, Diagnosis, and Treatment Explained

Wilms Tumor in Children: Causes, Symptoms, Diagnosis & Treatment Options

Wilms tumor is a rare type of kidney cancer that primarily affects young children. Because its symptoms—such as abdominal swelling or pain—can sometimes be mistaken for other common childhood conditions, understanding Wilms tumor early is especially important. This comprehensive guide provides clear, compassionate, and easy-to-understand information about Wilms tumor—covering its symptoms, how it is diagnosed, available treatment options, and what to expect throughout the journey. Our goal is to help you feel informed, supported, and empowered to face this condition with confidence and hope.

What Is Wilms Tumor?

Wilms tumor, also known as nephroblastoma, is a rare and highly treatable kidney cancer that is almost exclusively found in children. It is the most common type of kidney cancer in children, and the fourth most common childhood cancer overall. Wilms tumor typically develops in children under the age of five.

The cancer starts in immature kidney cells, which are cells that normally mature into functioning kidney tissue as a child develops. In Wilms tumor, some of these cells do not mature and instead multiply uncontrollably to form a solid tumor. The tumor is most often found when a parent or doctor notices a lump or swelling in a child's abdomen. The good news is that with early detection and modern, specialized treatment, the prognosis for children with Wilms tumor is excellent, with a very high cure rate.

Types of Wilms Tumor

Wilms tumor is a single disease, but it has a very wide range of behaviors. The main classification that a doctor will use to guide treatment is the tumor's "histology," which is how the cancer cells look under a microscope.

• Favorable Histology: This is the most common type of Wilms tumor, accounting for about 90% of cases. The cancer cells are abnormal but do not have certain large defects in their DNA. This type of tumor is highly sensitive to chemotherapy and has an excellent prognosis.
• Anaplastic Histology: This is a less common and more aggressive type of Wilms tumor. The cancer cells have a very distorted and abnormal appearance, which makes them more resistant to standard chemotherapy. This type requires more intensive treatment and has a lower prognosis.

Doctors also classify Wilms tumor based on whether it affects one kidney (unilateral) or both kidneys (bilateral). Most Wilms tumors are unilateral, but in about 5-10% of cases, they are bilateral.

What Are the Causes and Risk Factors for Wilms Tumor?

In the vast majority of cases, the exact cause of Wilms tumor is unknown. It is not caused by a single factor, but rather a random genetic mutation that occurs during a child's lifetime. However, researchers have identified several factors that may increase a child's risk.

1. Genetic Syndromes and Birth Defects: In about 10% of cases, Wilms tumor is linked to certain rare genetic syndromes or birth defects. These include:

• WAGR syndrome: A very rare syndrome that is characterized by Wilms tumor, aniridia (the absence of the iris of the eye), genitourinary abnormalities, and developmental delays.
• Beckwith-Wiedemann syndrome: This syndrome is characterized by an oversized arm or leg on one side of the body (hemihypertrophy), a large tongue, and an increased risk of childhood cancers, including Wilms tumor.
• Denys-Drash syndrome: This very rare syndrome includes diseased kidneys, a high risk of Wilms tumor, and reproductive organ abnormalities.

2. Family History: In a very small number of cases (1-2%), Wilms tumor can be inherited. This is caused by a gene mutation that is passed down from a parent to a child.

3. Age and Gender: Wilms tumor is most common in young children, with the average age of diagnosis being around 3 to 4 years old. Girls are slightly more likely to be diagnosed with Wilms tumor than boys.

It is important to remember that most children with Wilms tumor have no known risk factors, and parents should not blame themselves for their child's diagnosis.

What Are the Symptoms of Wilms Tumor?

The symptoms of Wilms tumor can be vague and are often mistaken for other common childhood illnesses. However, if you notice these symptoms, especially if they are persistent, it is important to see a doctor for a proper evaluation.

Common Early Signs:

• A Lump or Swelling in the Abdomen: The most common sign of Wilms tumor is a painless lump or swelling in the child's abdomen. Parents may notice that a child's stomach looks bigger than before or that a diaper suddenly fits too tightly.
• Abdominal Pain: The child may experience persistent abdominal pain.
• Blood in the Urine (Hematuria): This is a red flag and requires immediate medical attention. The urine may appear pink, red, or dark brown.
• Fever: A persistent, unexplained fever.

Advanced Symptoms:

As the cancer progresses, other symptoms may appear:

• High Blood Pressure (Hypertension): The tumor can produce hormones that cause a child's blood pressure to rise.
• Nausea and Vomiting
• Loss of Appetite
• Fatigue: Feeling unusually tired or a general lack of energy.
• Trouble Breathing: If the cancer has spread to the lungs, it can cause a persistent cough or shortness of breath.

If you have a gut feeling that something is wrong with your child, do not hesitate to seek medical attention.

How Is Wilms Tumor Diagnosed?

Diagnosing Wilms tumor requires a series of specialized tests to confirm the presence of a tumor, determine its type and location, and see if it has spread. The process often begins when a parent or a pediatrician notices a suspicious symptom.

Diagnostic Steps and Tests:

1. Physical Exam: Your child's doctor will perform a thorough physical exam, feeling the child's abdomen for a lump or swelling. They will also take the child's blood pressure.

2. Blood and Urine Tests: Blood tests are crucial to assess a child's overall health and kidney function. A urine test is performed to check for blood in the urine.

3. Imaging Scans: Imaging scans are the most important tool for finding a Wilms tumor.

• Abdominal Ultrasound: An ultrasound is a non-invasive scan that uses sound waves to create images of the kidneys and other organs. It can help doctors see the size and location of the tumor.
• CT (Computed Tomography) Scan: A CT scan provides detailed, cross-sectional images of the abdomen and chest. It can help doctors see the exact size of the tumor, whether it has spread to nearby structures, and whether it has spread to the lungs.

4. Biopsy: A biopsy is the surgical removal of a small tissue sample to be examined by a pathologist. For Wilms tumor, a biopsy is often not done before surgery because of the risk of spreading cancer cells. Instead, the entire tumor is removed with surgery, and the pathologist examines it to confirm the diagnosis and determine the histology.

It is highly recommended that the treatment be done at a specialized cancer center with a team experienced in pediatric oncology.

Staging and Grading of Wilms Tumor

The staging of Wilms tumor is a key factor in determining the treatment plan and predicting a patient's prognosis. The stage describes how far the cancer has spread. The most common staging system is a five-stage system.

• Stage I: The tumor is completely contained within one kidney and was completely removed with surgery.
• Stage II: The tumor has grown beyond the kidney into nearby fatty tissue or blood vessels, but was completely removed with surgery.
• Stage III: The tumor has spread to nearby lymph nodes or other structures in the abdomen, or cancer cells were found at the edge of the surgical sample. The tumor was not completely removed with surgery.
• Stage IV: The cancer has spread to distant parts of the body, such as the lungs, liver, or bones.
• Stage V: Tumors are found in both kidneys at the time of diagnosis.

In addition to the stage, doctors use the tumor's histology (favorable vs. anaplastic) to help guide treatment.

What Are the Treatment Options for Wilms Tumor?

The treatment plan for Wilms tumor is highly personalized and depends on the stage, the tumor's histology, and the child's age and overall health. A multidisciplinary team of specialists, including a pediatric surgeon, a pediatric oncologist, and a radiation oncologist, will work together to create a comprehensive treatment plan.

1. Surgery

Surgery is the primary treatment for most Wilms tumors. The goal is to remove the entire tumor.

• Radical Nephrectomy: The surgical removal of the affected kidney and any surrounding tissue, such as nearby lymph nodes. This is the most common surgery for a unilateral Wilms tumor.
• Partial Nephrectomy: For very small tumors or for a child with bilateral Wilms tumor, a surgeon may be able to remove only the tumor while saving the rest of the kidney.

2. Medical Treatment (Chemotherapy)

• Chemotherapy: Chemotherapy is a key part of the treatment for all stages of Wilms tumor. It is almost always given before or after surgery to kill any remaining cancer cells. For high-risk tumors, more intensive chemotherapy is used.

3. Radiation Therapy

Radiation therapy uses high-energy rays to kill cancer cells. It is often used for:

• Stage III and IV tumors: Radiation may be given to the abdomen after surgery to kill any remaining cancer cells.
• Lung Metastases: If the cancer has spread to the lungs, radiation to the chest may be given to kill the cancer cells.

4. Proton Therapy

Proton therapy is a highly advanced form of radiation that uses proton beams instead of X-rays. Because protons can be precisely aimed to deliver a high dose of radiation directly to the tumor while sparing nearby healthy tissues and organs, it may be a good option for Wilms tumor, as it can reduce the long-term side effects of radiation on a child's developing organs.

Prognosis and Survival Rates for Wilms Tumor

The prognosis (the likely outcome of the disease) for Wilms tumor has improved dramatically in recent decades. The outlook depends on the tumor's stage and histology.

Prognostic Factors: The most important factors affecting prognosis are the stage of the cancer at diagnosis, the tumor's histology (favorable vs. anaplastic), and the child's age and overall health.

Survival Rates: The overall 5-year survival rate for children with Wilms tumor is approximately 90%.

• Favorable Histology: For localized Wilms tumor with a favorable histology, the 5-year survival rate is over 95%.
• Anaplastic Histology: The prognosis is not as good, but with new treatments, the prognosis is improving.

It is important to discuss your child's specific prognosis with your oncology team, as they can provide a more accurate picture based on the unique characteristics of the tumor.

Screening and Prevention of Wilms Tumor

There are no routine screening tests for Wilms tumor in the general population. The best way to ensure early detection is for parents and pediatricians to be aware of the symptoms.

Prevention Strategies:

• Since the causes are not fully known, there is no known way to prevent Wilms tumor.
• For children with a known genetic syndrome that increases their risk, a doctor may recommend regular abdominal ultrasounds to check for any signs of the tumor.

For International Patients: Your Seamless Journey to Apollo Hospitals

Apollo Hospitals is a leading medical destination for international patients seeking high-quality and affordable cancer care. Our dedicated International Patient Services team is here to ensure your entire experience is as smooth and comfortable as possible. We have extensive experience treating children with complex conditions, including Wilms tumor.

Our Services for International Patients Include:

• Travel and Visa Assistance: We will provide you with a visa invitation letter and help with travel arrangements.
• Airport Transfers: We will arrange for a car to pick you up from the airport.
• Personalized Care: A dedicated patient coordinator will be your single point of contact, assisting with hospital admission, language interpretation, and any other needs you may have.
• Accommodation: We can assist you with booking suitable accommodation for you and your family near the hospital.
• Child Life Specialists: Our team includes child life specialists who can help your child and your family cope with the emotional and psychological challenges of a cancer diagnosis.
• Post-Treatment Follow-up: We will stay in touch with you after your return home to ensure a smooth recovery.

Frequently Asked Questions (FAQs) About Wilms Tumor

Q1: Is Wilms tumor curable?

A: Yes, Wilms tumor is highly curable. With modern, intensive treatments, the cure rate is very high, especially for early-stage disease. A combination of surgery and chemotherapy can lead to a long-lasting remission or a complete cure.

Q2: What is the survival rate for Wilms tumor?

A: The survival rate for Wilms tumor is excellent. The overall 5-year survival rate for children is approximately 90%. For localized disease with favorable histology, the 5-year survival rate is over 95%. Your doctor can provide a more accurate prognosis based on your child's specific case.

Q3: What are the side effects of Wilms tumor treatment?

A: Side effects vary with the type of treatment. Chemotherapy can cause fatigue, nausea, hair loss, and a weakened immune system. Surgery can cause pain and require a long recovery time. Radiation may cause skin irritation. Your medical team will work closely with you to manage these side effects.

Q4: Can Wilms tumor come back (recurrence)?

A: Yes, there is a risk of recurrence. This is why regular follow-up appointments and monitoring are crucial for early detection of any relapse.

Q5: What is the typical recovery time after surgery for Wilms tumor?

A: The recovery time depends on the complexity of the surgery. For a radical nephrectomy, a full recovery can take a few weeks. For more complex surgeries, recovery can be longer. Your surgeon will provide a detailed recovery plan.

Q6: Can a child live a normal life with one kidney?

A: Yes. The human body is designed to function with only one kidney. The remaining kidney will often grow larger and take on the work of both kidneys.

Q7: How is Wilms tumor different from other kidney cancers?

A: Wilms tumor is a pediatric cancer that starts in immature kidney cells. It is very different from adult kidney cancers, such as renal cell carcinoma, which start in the mature filtering cells of the kidney. They have different treatments and prognoses.

Q8: Can a baby be born with Wilms tumor?

A: Yes. In rare cases, Wilms tumor can be found in a fetus during a prenatal ultrasound.

Q9: Is a Wilms tumor diagnosis the parent's fault?

A: No. In the vast majority of cases, a Wilms tumor is not caused by anything a parent did or didn't do. It is caused by a random genetic mutation.