What is Wilms Tumor? Symptoms, Causes, & Treatment

Wilms tumor is a type of kidney cancer that primarily affects children, typically developing before age 5. This tumor grows from the cells that form the kidneys during a baby's development in the womb, which is why it almost always appears in very young children.

While hearing "kidney cancer" can feel overwhelming, there's reason for hope. Wilms tumor has one of the highest cure rates among childhood cancers, with over 90% of children going on to live healthy, normal lives after treatment. Understanding what you're dealing with can help you feel more prepared and confident as you navigate this journey.

What is Wilms Tumor?

Wilms tumor is a kidney cancer that starts in the developing kidney tissue of children. It's named after Dr. Max Wilms, who first described it in detail over a century ago.

This tumor forms when certain kidney cells that should have disappeared during normal development continue growing abnormally. Think of it like construction materials that were supposed to be cleaned up after building a house, but instead kept piling up in the wrong place. Most cases affect just one kidney, though about 5-10% of children develop tumors in both kidneys.

Wilms tumor is the most common type of kidney cancer in children, affecting about 1 in every 10,000 children. It's quite rare overall, with roughly 500-600 new cases diagnosed each year in the United States.

What are the Symptoms of Wilms Tumor?

The most common sign is a painless swelling or lump in your child's belly that you might notice during bath time or when your child is lying down. Many parents describe it as feeling like a firm mass on one side of the abdomen.

Here are the symptoms to watch for, keeping in mind that many children may have only one or two of these signs:

• A painless lump or swelling in the belly that you can feel
• Blood in the urine, which might look pink, red, or cola-colored
• Belly pain or discomfort
• Fever without an obvious cause
• Loss of appetite or feeling full quickly
• Nausea or vomiting
• Constipation from the tumor pressing on nearby organs
• High blood pressure (though this usually requires medical equipment to detect)

Less commonly, some children might experience shortness of breath if the cancer has spread to the lungs, or feel generally unwell and tired. Remember that these symptoms can have many other, more common causes, so finding one doesn't necessarily mean cancer is present.

What Causes Wilms Tumor?

Wilms tumor develops when kidney cells that should stop growing during normal development continue to multiply abnormally. The exact trigger for this process isn't fully understood, but researchers have identified several contributing factors.

Most cases happen by chance without any clear cause. However, some children are born with genetic changes that make them more likely to develop this tumor. These genetic factors account for about 10-15% of cases.

Here are the known contributing factors:

• Genetic mutations that occur during kidney development in the womb
• Inherited genetic syndromes like WAGR syndrome or Beckwith-Wiedemann syndrome
• Birth defects affecting the genitals or urinary system
• Family history of Wilms tumor (though this is quite rare)
• Certain genetic conditions that affect normal cell growth

It's important to understand that nothing you did or didn't do during pregnancy caused this tumor. Wilms tumor isn't caused by environmental factors, diet, or lifestyle choices. It's simply an unfortunate result of how some children's kidneys develop.

When to See a Doctor for Wilms Tumor?

You should contact your child's doctor promptly if you notice a lump or swelling in your child's belly that persists for more than a few days. Even though most belly lumps in children aren't cancer, it's always worth getting checked.

Seek medical attention within a day or two if your child has blood in their urine, especially if it's accompanied by other symptoms like belly pain or fever. While blood in urine can have many causes in children, it's something that should always be evaluated by a healthcare provider.

Call your doctor right away if your child has severe belly pain, persistent vomiting, or seems unusually unwell. Trust your instincts as a parent - if something feels wrong or different about your child's health, it's always okay to seek medical advice.

What are the Risk Factors for Wilms Tumor?

Several factors can increase a child's chances of developing Wilms tumor, though having these risk factors doesn't mean your child will definitely get cancer. Most children with these factors never develop tumors.

The strongest risk factors are certain genetic conditions and birth defects that affect normal development:

• WAGR syndrome (affects the eyes, genitals, and intellectual development)
• Beckwith-Wiedemann syndrome (causes overgrowth of body parts)
• Denys-Drash syndrome (affects kidney function and genital development)
• Birth defects of the genitals or urinary system
• Having an undescended testicle
• Family history of Wilms tumor (though this accounts for less than 2% of cases)

Some less common risk factors include certain genetic mutations and being born with kidney tissue that didn't develop normally. African American children have a slightly higher risk than other ethnic groups, though the reasons for this aren't fully understood.

Age is also a factor, with most cases occurring between ages 2 and 5. It's extremely rare in children older than 10.

What are the Possible Complications of Wilms Tumor?

When caught early and treated appropriately, most children with Wilms tumor recover completely without long-term problems. However, like any serious medical condition, there can be complications related to both the tumor itself and its treatment.

Complications from the tumor might include:

• The tumor growing large enough to press on nearby organs
• High blood pressure from kidney involvement
• Kidney function problems if both kidneys are affected
• Spread to other parts of the body, most commonly the lungs or liver
• Rupture of the tumor, which can happen during examination or surgery

Treatment-related complications, while manageable, can include effects from chemotherapy like temporary hair loss, increased infection risk, or nausea. Radiation therapy might cause skin irritation or, rarely, affect growth of treated areas. Surgery risks include typical surgical complications like bleeding or infection.

Long-term effects are uncommon but can include hearing problems from certain chemotherapy drugs or, very rarely, development of other cancers later in life. Your medical team will monitor for these possibilities and take steps to minimize risks.

How is Wilms Tumor Diagnosed?

Diagnosis typically starts with your pediatrician examining your child and feeling for any lumps or swelling in the belly. If something concerning is found, you'll likely be referred to a pediatric specialist for further testing.

The diagnostic process usually involves several imaging tests to get a clear picture of what's happening. An ultrasound is often the first test because it's painless and doesn't use radiation. This can show if there's a mass in the kidney and help determine its size and characteristics.

Additional tests typically include:

1. CT scan or MRI to get detailed images of the tumor and check if it has spread
2. Chest X-ray or CT scan to look for any spread to the lungs
3. Blood tests to check kidney function and overall health
4. Urine tests to look for blood or other abnormalities
5. Sometimes, a small tissue sample (biopsy) to confirm the diagnosis

The entire diagnostic process usually takes a few days to a week. While waiting for results can feel stressful, remember that getting an accurate diagnosis is the first step toward the most effective treatment plan for your child.

What is the Treatment for Wilms Tumor?

Treatment for Wilms tumor is highly successful, with cure rates exceeding 90% when the cancer is caught early. The treatment plan depends on the tumor's size, location, and whether it has spread, but typically involves a combination of surgery and chemotherapy.

Most children will have surgery to remove the affected kidney (called a nephrectomy) along with the tumor. Don't worry - people can live completely normal lives with one healthy kidney. Before surgery, your child might receive chemotherapy to shrink the tumor and make it easier to remove safely.

The typical treatment approach includes:

1. Pre-surgery chemotherapy (usually 4-6 weeks) to shrink the tumor
2. Surgery to remove the kidney and tumor
3. Additional chemotherapy after surgery (typically 6-24 weeks)
4. Radiation therapy in some cases, particularly if the cancer has spread
5. Regular follow-up visits to monitor recovery and watch for any recurrence

For children with tumors in both kidneys, the approach is more complex and focuses on preserving as much kidney function as possible. This might involve partial removal of kidney tissue rather than complete kidney removal.

Treatment is usually completed within 6-9 months, and most children return to their normal activities relatively quickly after finishing therapy.

How to Provide Home Care During Treatment?

Caring for your child at home during treatment focuses on keeping them comfortable, preventing infections, and maintaining as much normalcy as possible. Your medical team will give you specific guidelines, but there are general principles that can help.

Managing side effects from treatment is often the biggest challenge. For nausea, offer small, frequent meals with bland foods that your child enjoys. Staying hydrated is crucial, so encourage sips of water, ice chips, or popsicles throughout the day.

Here are key home care strategies:

• Keep your child away from people who are sick, as chemotherapy can weaken the immune system
• Wash hands frequently and encourage your child to do the same
• Monitor for fever and call your medical team immediately if it occurs
• Provide extra rest time and don't worry if your child sleeps more than usual
• Offer nutritious foods when your child feels like eating, but don't force meals
• Keep the surgical site clean and dry according to your surgeon's instructions
• Give medications exactly as prescribed, even if your child feels better

Emotionally, maintain routines when possible and continue with activities your child enjoys, modified as needed for their energy level. Many families find that staying connected with school friends and keeping up with favorite hobbies helps children feel more normal during treatment.

How Should You Prepare for Doctor Appointments?

Being prepared for medical appointments can help you get the most out of your time with the healthcare team and ensure all your concerns are addressed. Start by writing down your questions before each visit - it's easy to forget important things when you're feeling stressed or overwhelmed.

Bring a complete list of all medications your child is taking, including over-the-counter medicines and any supplements. Also, keep a simple diary of symptoms, side effects, or changes you've noticed since the last visit.

Consider preparing these items:

• A list of current symptoms and when they started
• Questions about treatment progress and what to expect next
• Any concerns about side effects or your child's daily activities
• Insurance cards and any required paperwork
• A trusted family member or friend for support and to help remember information
• Something to keep your child occupied during waiting times
• Snacks and drinks in case the appointment runs long

Don't hesitate to ask for clarification if medical terms are confusing, and request written instructions for complex care directions. Many parents find it helpful to take notes or ask if they can record important parts of the conversation to review later.

What's the Key Takeaway About Wilms Tumor?

The most important thing to remember is that Wilms tumor, while serious, has an excellent prognosis when properly treated. Over 90% of children diagnosed with this cancer go on to live completely normal, healthy lives after treatment.

Early detection makes a significant difference in treatment success, so trust your instincts if you notice any concerning changes in your child's health. The combination of surgery and chemotherapy is highly effective, and most children complete treatment within less than a year.

While the journey ahead may feel overwhelming right now, you're not alone. Pediatric cancer teams are specially trained to care for both children and families through this process. Many families find that connecting with other parents who have been through similar experiences provides valuable support and perspective.

Remember to take care of yourself too - your child needs you to be as healthy and strong as possible. Accept help from friends and family, and don't hesitate to use the support services available through your medical center.