Wilms tumor is the most common type of pediatric kidney cancer. It is most common in children age five and younger, but it can also occur from infancy to age 15. As with any cancer, the tumor can spread beyond its initial location.
What are the causes and symptoms of Wilms tumor?
Occasionally, a child may have a genetic syndrome that could predispose them to this cancer and other kidney conditions. Usually, however, there is no known cause for the development of this disease.
The most common symptom of Wilms tumor is the sudden appearance of a solid mass in the abdomen. Symptoms can vary between children, but some other symptoms may include:
- High blood pressure
- Decreased appetite
- Weakness or tiredness
- Blood in the urine
- Swelling of the abdomen
- Abdominal pain
Please note that these symptoms may resemble other more common conditions or medical problems. Always consult your child’s physician if you have any concerns about their health.
How is Wilms tumor diagnosed?
If a tumor is suspected, the first test will be an abdominal ultrasound. If the ultrasound reveals a tumor, a chest or abdominal X-ray or CT scan will help determine the size, location, and spread of the tumor. An MRI can also be used to look for tumor spread in blood vessels and other organs and is commonly used for children with bilateral renal tumors (on both sides of the abdomen). Blood and urine tests will be used to evaluate the child’s kidney and liver function as well as any other blood-related abnormalities. Occasionally, the child will have a biopsy to determine tumor type.
Wilms tumor can be categorized into five stages, ranging from stage I, where the tumor is limited to the kidney and can be completely removed surgically, to stage V, where the tumor is found on both kidneys.
How is Wilms tumor treated?
Treatment will be personalized based on:
- Extent of the disease (stage)
- How the child’s doctor expects the disease to progress
- Type, location, and size of the tumor
- Genetic characteristics of the tumor
- The child’s age, overall health, and medical history
- The child’s tolerance for specific medications, procedures, or therapies
However, the first step in treatment is to surgically remove the tumor. Typically, a radical nephrectomy will be the recommended procedure. This will remove the whole kidney, the tissue around the kidney, the ureter, and the adrenal gland. This operation is performed if the tumor is contained to one kidney. In some low-stage cases, the condition can be treated by this surgery alone.
If a child has bilateral Wilms tumor or a known predisposition to kidney cancer, the physician may recommend a kidney-sparing surgery called a partial nephrectomy. This removes the tumor and leaves the maximum amount of healthy tissue.
In rare cases, when the tumor is very large, chemotherapy may be used to shrink the tumor before surgery.
After surgery, a child will usually receive chemotherapy and sometimes radiation therapy. These are determined by the spread of the tumor. In very rare cases, a stem cell transplant of the child’s own cells may be used.
What is the outlook for patients with Wilms tumor?
Most children are successfully treated for Wilms tumor with prompt medical attention, aggressive therapy, and continued follow-up care. As with any cancer, survival varies greatly from patient to patient depending on a variety of factors, including:
- Extent of the disease
- Size of the primary tumor
- Genetic changes in the tumor
- Histology of the tumor (its appearance under the microscope)
- The child’s tolerance of specific medications, procedures, or therapies
- Age and overall health of the child at diagnosis
- Response to therapy
Children can be at risk for long-term and late-effects of the cancer and treatment. This includes high blood pressure, heart and lung problems, and slowed or decreased growth and development. In children with bilateral kidney tumors or with a predisposition syndrome that causes kidney abnormalities, reduced kidney function may appear.
Even with rare or hard-to-treat conditions, there are always options for children, including clinical trials. Wilms tumor is continuously researched, and the prognosis will continue to improve in the years to come.