Wilms tumor, also known as nephroblastoma, is a rare kidney cancer that primarily affects children, usually between the ages of 3 and 4, and is the most common type of kidney cancer in children. About 500 cases of Wilms tumor are diagnosed annually in the United States, making up about 5% of all childhood cancers. The tumor usually affects one kidney but can occur in both in rare cases. Wilms tumor is highly treatable, and the prognosis is generally favorable, especially when caught early. (Source)
What is Childhood Wilms Tumor?
Wilms tumor is a cancer that begins in the kidneys, which are vital organs responsible for filtering waste and balancing fluids in the body. This type of tumor develops from immature kidney cells that grow uncontrollably due to genetic mutations. It often forms as a single mass, but in about 5% of cases, tumors can develop in both kidneys.
The tumor can vary in size, and the extent of the disease can range from a localized mass to one that has spread to other parts of the body. Because of advancements in treatment, survival rates for Wilms tumor are high, particularly for children with early-stage disease. (Source)
Also, read: Now Know All about Childhood Neuroblastoma: Cause, Symptoms, Diagnosis, Treatment
Causes of Childhood Wilms Tumor
The exact cause of Wilms’ tumor is still unknown. However, several genetic and environmental factors may contribute to its development.
- Genetic Mutations: Most Wilms tumors result from sporadic genetic changes (mutations) that occur during fetal development, causing immature kidney cells to become cancerous. These mutations can affect certain genes that control cell growth, including the WT1 and WT2 genes located on chromosome 11.
- Syndromes and Genetic Conditions: Certain genetic syndromes increase the risk of developing Wilms tumor, including:
- WAGR syndrome: A rare genetic condition involving the WT1 gene.
- Beckwith-Wiedemann syndrome: Involves overgrowth of certain body tissues and organs.
- Denys-Drash syndrome: A disorder of the kidneys and genitals that also involves the WT1 gene.
Children with these syndromes have a higher risk of developing Wilms tumor, and their cancer is often detected at a younger age. (Source)
How Does Wilms Tumor Spread?
Like other cancers, Wilms tumor can spread (metastasize) to other body parts. The most common sites for metastasis include:
- Lymph nodes: Cancer cells can spread to the lymphatic system, affecting lymph nodes near the kidney or in other body areas.
- Lungs: The lungs are the most common site of metastasis, causing breathing difficulties if the tumor spreads here.
- Liver: In some cases, the tumor can spread to the liver.
- Bones and Brain: Although rare, Wilms tumor can also metastasize to the bones or brain.
If the tumor is detected and treated before it spreads beyond the kidney, the prognosis is generally excellent. (Source)
Symptoms of Childhood Wilms Tumor
Symptoms of Wilms tumor can vary depending on the size of the tumor and whether it has spread to other parts of the body. In its early stages, the tumor may cause no symptoms at all, but as it grows, common symptoms may include:
- Abdominal swelling or mass: Often the first noticeable sign, this painless swelling may be discovered during bathing or dressing.
- Abdominal pain: As the tumor grows, it can cause discomfort or pain in the abdomen.
- Fever: A persistent or unexplained fever may occur.
- Blood in the urine (hematuria): This is a common sign of kidney-related issues, including Wilms tumor.
- Loss of appetite and weight loss: As the tumor grows, children may experience reduced appetite and weight loss.
- High blood pressure: The tumor can interfere with kidney function, leading to increased blood pressure.
- Fatigue: Children may experience general fatigue or low energy levels. (Source)
Diagnosis of Childhood Wilms Tumor
A diagnosis of Wilms tumor involves several steps, starting with a thorough medical history and physical examination. To confirm the presence and stage of the tumor, several diagnostic tests are used:
- Imaging Tests: These help detect the tumor and determine whether it has spread.
- Ultrasound: The first imaging test often used to detect a mass in the kidney.
- CT (Computed Tomography) Scan or MRI (Magnetic Resonance Imaging): These provide detailed images of the kidney and surrounding areas.
- Chest X-ray or Chest CT: If the doctor suspects that the cancer has spread to the lungs.
- Blood and Urine Tests: These tests help assess kidney function and detect other health issues that may arise from the tumor.
- Biopsy or Surgery: In some cases, a biopsy is performed to confirm the diagnosis by removing a small sample of tissue from the tumor for analysis. In many cases, however, the tumor is removed surgically as the first step of treatment, and the tissue is then analyzed to confirm the diagnosis.
- Staging: Once diagnosed, Wilms tumor is staged from Stage I (localized to the kidney) to Stage V (tumors in both kidneys). The stage helps guide treatment decisions.
Treatment of Childhood Wilms Tumor
Treatment for Wilms tumor depends on the stage of the cancer and whether it has spread to other parts of the body. Common treatment options include:
- Surgery:
- Nephrectomy: The most common treatment for Wilms tumor, which involves the removal of the affected kidney. In some cases, a partial nephrectomy may be performed to preserve some kidney function, especially if both kidneys are affected.
- Bilateral Tumors: If the tumor is present in both kidneys, a surgeon may remove as much of the tumor as possible from each kidney without completely removing both kidneys.
- Chemotherapy:
- Chemotherapy is often used before or after surgery to shrink the tumor or kill any remaining cancer cells. It is particularly useful for high-risk or advanced-stage tumors.
- Radiation Therapy:
- Radiation therapy may be used in combination with surgery and chemotherapy for children with Stage III or IV Wilms tumors. It helps kill cancer cells that may have spread to nearby tissues or the lungs.
- Targeted Therapy:
- Targeted therapies are being researched and may be used to treat tumors with specific genetic mutations, such as those involving the WT1 gene. (Source)
Can Childhood Wilms Tumor Be Prevented?
There is no known way to prevent Wilms tumor because the causes are primarily genetic and occur during fetal development. Routine prenatal care and early detection of associated syndromes or birth defects can help monitor children at risk. However, for most children, the tumor develops sporadically without any clear environmental triggers.
Is Childhood Wilms Tumor Hereditary?
In most cases, Wilms tumor is not hereditary and occurs sporadically. However, about 1-2% of cases are linked to inherited genetic conditions, including:
- WAGR syndrome
- Beckwith-Wiedemann syndrome
- Denys-Drash syndrome
Children with a family history of Wilms tumor or certain genetic syndromes should be monitored closely for signs of the disease. (Source)
Also, watch web stories: 7 Facts You Need to Know About Neuroblastoma
Can Childhood Wilms Tumor Be Cured?
The prognosis for Wilms tumor is generally very favorable, especially when diagnosed early. The cure rates for Wilms tumor depend on the stage of the disease:
- Stage I and II: Children with Stage I or II tumors that have not spread have a 90% or higher survival rate with proper treatment.
- Stage III and IV: Even for children with more advanced tumors, survival rates range from 70-90%, depending on the extent of the spread and response to treatment.
- Stage V: For children with tumors in both kidneys, the survival rate is around 60-80%, though it varies depending on how much kidney tissue can be preserved and the aggressiveness of treatment.
Long-term follow-up is essential for monitoring potential late effects of treatment, such as kidney function or secondary cancers, but most children go on to lead healthy lives after treatment.
Conclusion
Childhood Wilms tumor is a rare but treatable kidney cancer that primarily affects young children. With advances in medical care, the survival rate for Wilms tumor is very high, especially when the tumor is diagnosed early. Genetic testing and ongoing research continue to improve understanding of the disease, leading to more effective treatments and better outcomes for children.
