Wilms' Tumor : A Common Cancer in Young Children

A Wilms' tumor is a clump of primitive cells that have remained in a child's kidney from early cell development. This clump of cells begin to multiply after birth, forming a large mass of abnormal cells.

Wilms' tumor is a cancer of the kidney that affects children almost exclusively. It's the most common malignant tumor of the kidney in children and it usually occurs about the age of 2 or 3 and rarely after age 8. Female are only slightly more likely to get a Wilms' tumor than males. The tumor is know as a nephroblastoma. About 1 in 10,000 children get this type of tumor.

It can occur in either kidney but very rarely (5%) affects both kidneys. In about 15% of cases the cancer has spread (metastasis). The most common sites in the body where metastasis occurs are the liver and lungs. You may detect a mass in your child's abdomen while bathing or dressing your child, or the doctor may discover it during an examination. Do not push on the abdomen and use care during bathing and dressing to avoid injury to the tumor site. A Wilms' tumor frequently goes undetected in its early stages because the tumor can grow quite large without causing pain. A Wilms' tumor can weigh up to 10 pounds. You may notice the following symptoms in your child:

Fever
Blood in the urine or an abnormal urine color
Reduced appetite
Weight loss
High blood pressure
Constipation
Stomach pain
Nausea
Vomiting
General discomfort (malaise)

Wilms' tumors are found more commonly in patients with other congenital conditions. A missing iris of the eye is a birth defect that sometimes is associated with Wilms' tumor. Also, the tendency to develop Wilms' tumors can run in families.

A Special emphasis is placed on the history and physical exam, looking for a family history of cancer and other birth defects in the child. The initial diagnosis of the tumor is done by ultrasound and CT scans and sometimes by I.V. pyelography, where die is injected into a vein to show the kidney structures. The final diagnosis occurs by obtaining a tissue sample from the mass by biopsy and examining it under a microscope to verify that it is a Wilms' tumor. Also chest x-rays and a CT scan of the lungs and bone marrow biopsy may be done to see if the tumor has spread.

The treatment for a Wilms' tumor consists of a combination of surgery, radiation and chemotherapy. During surgery, lymph nodes, abdominal organs and other tissues are examined and removed if the tumor has spread to those areas. In very young children the surgery and chemotherapy to kill cancer cells that may have spread to other parts of the body may be enough without radiation therapy.

Spread of the tumor to the liver, lungs, bone or brain is the worst complication. Also high blood pressure and kidney damage may occur as a result of the tumor or the treatment. Removal of Wilms' tumor present in both kidneys may leave the patient with borderline kidney function.

Wilms' tumor has a high cure rate, especially if the tumor was localized (no spread to other parts of the body). About 90% of all children are cured by this combined approach.

If is very important to call your health care provider if you discover an abdominal mass in your child, blood or unusual colored urine or any other symptom suggestive of Wilms' tumor.