Understanding Wilms Tumor: Symptoms, Causes, and Treatment Options for Kidney Cancer in Children

Creator: Doctronic
Published: 2023-05-13

Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on May 13th, 2023.

Key Takeaways

This kidney cancer peaks between ages 3-4 and represents 90% of all childhood kidney tumors, with approximately 500 new cases diagnosed annually in the United States.
The hallmark sign is a painless abdominal mass that parents can often feel during bathing or dressing, accompanied by asymmetrical belly swelling on one side.
Children with birth defects like aniridia (missing iris) have a 1 in 3 chance of developing this cancer, while WAGR syndrome carriers face even higher risks.
Treatment follows a precise protocol: biopsy and imaging first, then 4-6 weeks of chemotherapy to shrink the tumor before surgical removal to prevent rupture.
Stage I and II cases achieve 95-98% cure rates, while even advanced Stage IV maintains 85-90% long-term survival with current treatment protocols.

Wilms tumor, also known as nephroblastoma, is the most common type of kidney cancer in children. It usually affects kids between the ages of 3 and 4, but it can occur in children up to age 5. Most children with Wilms tumor have a tumor on one kidney, but about 5% develop tumors on both kidneys.

Symptoms of Wilms Tumor

Some children with Wilms tumor may not experience any symptoms, while others may have:

Belly pain
Swelling in the belly
A visible or palpable growth in the belly
Fever
Nausea
Lack of appetite
High blood pressure
Blood in the urine
Constipation
Shortness of breath

Wilms tumors can grow quite large before being noticed, sometimes weighing up to 1 pound.

Causes and Risk Factors

Wilms tumor occurs when kidney cells grow abnormally and turn into cancer cells. This is usually due to a random change in a gene, but in rare cases, it can be caused by inherited gene changes. Certain factors may increase a child's risk of developing Wilms tumor, including:

Age (between 3 and 5 years old)
Gender (girls are more likely than boys)
Race (slightly higher risk in Black children)
Family history of Wilms tumor
Birth defects (cryptorchidism, hypospadias, aniridia, hemihypertrophy)
Other health conditions (WAGR syndrome, Denys-Drash syndrome, microcephaly, Beckwith-Wiedemann syndrome)

Diagnosing Wilms Tumor

To diagnose Wilms tumor, your child's doctor will perform a physical exam, take a medical history, and order various tests, such as:

Blood tests to assess kidney and liver function, blood cell counts, and clotting ability
Urine tests to check for blood
Imaging tests (ultrasound, MRI, or CT scan) of the belly
Biopsy to examine tumor cells under a microscope
Additional imaging tests to determine if the cancer has spread
Bone scan to look for diseased bone

Understanding Wilms Tumor: Symptoms, Causes, and Treatment Options for Kidney Cancer in Children

Staging Wilms Tumor

Wilms tumors are staged based on how far the cancer has spread:

Stage I: Tumor is confined to one kidney and can be completely removed by surgery
Stage II: Cancer has spread to the area around the kidney but can be completely removed by surgery
Stage III: Cancer hasn't spread outside the abdomen but cannot be completely removed by surgery
Stage IV: Cancer has spread to distant parts of the body (lungs, bones, brain) or to lymph nodes outside the belly
Stage V: Tumors are present in both kidneys

Treatment Options for Wilms Tumor

Treatment for Wilms tumor depends on the stage of the cancer and may include:

Surgery

Partial nephrectomy: Removal of the tumor and some surrounding healthy tissue
Radical nephrectomy: Removal of the affected kidney, ureter, adrenal gland, and nearby tissue
Removal of both kidneys: In some cases, both kidneys may need to be removed, requiring dialysis and possibly a kidney transplant

Chemotherapy

Chemotherapy uses medications to fight or kill cancer cells throughout the body. Most children with Wilms tumor will receive chemotherapy at some point during treatment. Side effects may include hair loss, fatigue, mouth sores, loss of appetite, nausea, vomiting, diarrhea, constipation, bruising, bleeding, and increased risk of infection.

Radiation Therapy

Radiation therapy uses high-energy beams to kill cancer cells. It is typically used for stage III and above tumors. Side effects can include tissue damage, so doctors use the lowest effective dose possible.

Outlook for Children with Wilms Tumor

The outlook for most children with Wilms tumor is good, with up to 90% of those with favorable histology tumors being cured. The cure rate is lower for tumors with unfavorable histology. After treatment, children will have regular follow-up visits to ensure they remain healthy. If you have any questions or concerns, don't hesitate to ask your child's doctor for clarification and guidance on how to best support your child.

For more information on Wilms tumor, visit:

The Bottom Line

Early detection of abdominal masses in young children leads to exceptionally high cure rates when treated at pediatric cancer centers following established protocols. Any unexplained abdominal swelling or mass in a child under 5 requires immediate medical evaluation. If you're concerned about potential symptoms, Doctronic can help connect you with appropriate pediatric specialists quickly.