What are the other Names for this Condition? (Also known as/Synonyms)

• Bilateral Wilms Tumor
• Kidney Tumor
• Nephroblastoma

What is Wilms’ Tumor? (Definition/Background Information)

• Wilms’ Tumor is an infrequent, malignant solid tumor of uncertain derivation; the cell of origin of this tumor is unknown. It affects the kidneys of very young children. 90% of all pediatric kidney tumors are Wilms’ Tumors
• Based on prognosis Wilms’ Tumor is mainly classified as: Favorable tumor and Unfavorable (anaplastic) tumor
• Favorable tumor is the milder form of Wilms’ Tumor and is more responsive to therapy. A majority of the cases are favorable
• Unfavorable tumor is more aggressive, is difficult to treat, and has a 1 in 20 chance of occurrence (5% probability)

Who gets Wilms’ Tumor? (Age and Sex Distribution)

• Young children in the age range of 3-4 years are normally affected by this disorder. Children over 6 years old, are not commonly affected
• Infrequently, adolescents and even adults have been found to suffer from Wilms’ Tumor
• Some studies have indicated the incidence as being higher in females than males
• Asians have the lowest risk; Africans and Afro-Americans have the highest risk for contracting this type of kidney tumor

What are the Risk Factors for Wilms’ Tumor? (Predisposing Factors)

Risk factors for Wilms’ Tumor include:

• A genetic predilection is observed. Individuals having had family members (past or present) with Wilms’ Tumor are at risk. If bilateral tumors are present then, it strongly indicates a genetic influence. But, it is important to note that a majority of patients with Wilms’ Tumor do not have a family history of the condition
• Birth anomalies/defects, such as those affecting the genitalia (specifically the urinary opening and testicles), absent or partially formed iris (part of the eye that gives it its distinct color), asymmetric body profile due to one part of the body appearing swollen or oversized; are all features that seem to be part of a syndrome, which indicates a higher possibility for the presence of Wilms’ Tumor
• Certain rare congenital conditions like Denys-Drash syndrome, Beckwith-Wiedemann syndrome, and WAGR syndrome have been associated with Wilms’ Tumor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Wilms’ Tumor? (Etiology)

• The exact cause of Wilms’ Tumor is unknown. However, cell study and genetic analysis have implicated certain cell irregularities that occur during kidney formation in the fetal stage, as a possible cause
• Some of the anomalous cell changes are due to inherited genetic conditions. In many cases, the reason why this happens remains unidentified; the anomalous cell changes are thought to occur spontaneously
• It is believed that external factors, such as lifestyle habits and environmental conditions, do not play a role in the formation of Wilms’ Tumor

What are the Signs and Symptoms of Wilms’ Tumor?

Normally, only one kidney is affected with Wilms’ Tumor (called unilateral condition). However, in about 10% of the cases, both kidneys may have tumorous growths (called bilateral condition). The signs and symptoms of Wilms’ Tumor include:

• Severely swollen abdomen and abdominal pain
• Fever, high blood pressure (sometimes)
• Vomiting, nausea, uneasiness, lethargy
• Loss of appetite
• Presence of blood in the urine (occasionally), unusual urine color
• Constipation

How is Wilms’ Tumor Diagnosed?

The main diagnostic tools that aid in detection of Wilms’ Tumor include:

• Physical exam with evaluation of family history, of the newborn/child/adult
• Blood analysis such as total blood count, creatinine levels, blood urea nitrogen tests
• Urine analysis
• Abdominal ultrasound
• MRI, CT scan of abdomen
• If the tumor has metastasized, then additional tests and scans may be performed. These tests may include chest x-rays and bone scans
• Removal of tumor with examination by a pathologist under a microscope, normally helps in arriving at a conclusive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Wilms’ Tumor?

The possible complications due to Wilms’ Tumor include:

• Metastasis, or the dissemination of Wilms’ Tumor to other locations, such as the bones, brain, liver, and lungs
• Recurrence of the tumor after its surgical removal
• Serious impairment of kidney necessitating removal of the kidney. Sometimes, both the kidneys may be affected resulting in a need for a kidney transplant
• Damage of vital nerves, blood vessels, and surrounding structures, during surgery
• Side effects of chemotherapy and radiation therapy

How is Wilms’ Tumor Treated?

The following are the treatment measures for Wilms’ Tumor:

• Once Wilms’ Tumor is confirmed, the child should not be allowed any physical activity that might potentially injure the stomach or abdominal region, until after the tumor is removed
• Treatment corroborates with the type of tumor (favorable or unfavorable), stage of the tumor at diagnosis (whether it has spread), and general health of the child. An intensive management of anaplastic (unfavorable) type tumor is required
• Surgical excision of Wilms’ Tumor (nephrectomy) with removal of the entire lesion, which is followed by radiation and chemotherapy course
• Sometimes, chemotherapy/radiotherapy is given prior to the operation to shrink the tumor
• Arterial embolization is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure
• Post-operative care is important; minimum activity level has to be ensured, until the surgical wound heals and health condition of the child normalizes
• Follow-up care with regular screening and check-ups are extremely important. This is essential to monitor disease-free state and to detect recurrences (if they do occur)

How can Wilms’ Tumor be Prevented?

• Wilms’ Tumor is a pediatric tumor of the kidneys with cancerous potential; it cannot be prevented
• For those who are planning a child, genetic counseling with genetic testing should be considered by individuals having a family history of Wilms’ Tumor
• If risk factors are high for a young child, or there are birth defects linked to Wilms’ Tumor, then kidney exam and scans are highly advisable. These tests should be performed as early as possible. It is recommended that such children undergo ultrasound scans of both the kidneys every 3 months, until the age of 6 years
• Regular medical screening at periodic intervals with tests, scans, and physical exam, are mandatory for those who have survived the illness. This is essential to help detect recurrences early

What is the Prognosis of Wilms’ Tumor? (Outcomes/Resolutions)

Histological (anatomical) type, tumor stage, and metastatic state, are main characteristics that define the prognosis for Wilms’ Tumor. The tumor prognosis is classified from Stage I to Stage V:

• Stage I: The tumor is confined to one kidney alone, which makes surgery a curable option
• Stage II: The tumor has spread from one kidney to the surrounding areas. Most of Stage II tumor can be removed completely through surgery
• Stage III: The tumor is confined to the abdominal region and not spread beyond the abdomen. In such cases, surgical removal of the entire tumor may not be possible. Other treatment measures like chemotherapy and/or radiation therapy may be necessary
• Stage IV: The tumor has spread beyond abdomen to distant sites, such as bones, brain, lungs, and liver. In such cases, surgery alone is not curative; other treatment modalities may be necessary
• Stage V: The tumor is present in both the kidneys. The occurrences of such tumors are independent of each other. In such cases, the surgeon would remove as much tumor as possible with the goal of keeping some functional kidney, since removing both kidneys will cause a kidney failure

Children with favorable type of tumor have a very good prognosis; over 90% survival rate after 5 years. Over 95% of all Wilms’ Tumor types are favorable. Children suffering from unfavorable (anaplastic) form of kidney tumor, and those tumors that are in their advanced stages, have the worst outcomes.

Sometimes, the tumor can be quite large and still be confined to the kidney, without metastasis. A large tumor does not always mean an advanced tumor stage.

Additional and Relevant Useful Information for Wilms’ Tumor:

There may be multiple tumors in both kidneys (Bilateral Wilms’ Tumor). It does not mean that the cancer has metastasized. It mostly implies that the child’s physiology is more genetically susceptible to the condition. Bilateral tumors are when two tumors occur independently, in both the kidneys.