What you Need to Know About Wilm’s Tumor

Image of the kidneys with a text reading Wilm's tumor.

Wilm’s tumor is a kidney cancer that predominantly affects children. Most kids with Wilm’s tumor are less than 5 years old. Wilm’s tumor also occurs in older children and adults.

Although it is a rare disease, Wilm’s tumor is the most common abdominal cancer in children and the 4th most common childhood cancer. Luckily, the survival rate is about 93% in 5 years.

What causes Wilm’s tumor?

Nobody knows the exact cause of this cancer but some genetic alterations have been linked. Experts also say Wilm’s tumor is more common among blacks. 

A family history of Wilm’s tumor is a risk factor but parents do not typically pass it on to their children.

Certain syndromes are associated with Wilm’s tumor. They include

  • Beckwith-Wiedemann syndrome in which the person has a large birth weight, large tongue, and enlargement of one side of the body
  • Denys Drash syndrome is characterized by pseudohermaphroditism
  • WAGR syndrome where the person has genital abnormalities, intellect problems, and absence of the iris. About half of those with this syndrome have Wilm’s tumor

What are the signs and symptoms of Wilms tumor?

People with Wilm’s tumor may have no symptoms in the initial stages. Over time, symptoms become more apparent. 

There may be abdominal swelling. This may appear as a preponderance of one side of the abdomen. 

Some may experience pain or discomfort on one side. For some, the discomfort is not severe, so it is easy to dismiss it at the onset.

Other findings include

  • recurrent fever
  • Blood in urine
  • Hypertension
  • Anemia
  • Urinary tract infections
  • Fatigue and weight loss.

Those who have advanced disease may complain of respiratory symptoms because of metastasis to the pulmonary system.

Diagnosis of Wilm’s tumor

A physical examination may suggest the presence of a mass in the abdomen. This often prompts an imaging request. Ultrasound is widely available and may be the initial imaging. It can detect the presence of a kidney tumor. A CT scan or an MRI of the abdomen may also be requested. These show the tumor and can indicate if there is infiltration of nearby structures or metastasis to other abdominal organs.

Your doctor may also ask for a chest X-ray or a chest CT scan to check for metastasis to the lungs.

Blood tests will also be ordered to check for anemia and to assess the kidney function.

A biopsy is necessary to confirm the diagnosis of Wilm’s tumor. A nephrectomy (surgical removal of the kidney) is done and the tissues are examined histologically. This allows your doctors to stage the disease and determine if there are favorable or unfavorable features.

Image of a man with back pain from the kidneys

Staging 

After a diagnosis of Wilm’s tumor, the disease will be staged. This helps your healthcare team determine the best approach to treating the condition.

Stage 1: The disease is still limited to the kidneys. Surgery will get rid of the tumor.

Stage 2: The disease has spread to structures very close to the kidneys like fat and blood vessels. Surgery can get rid of the tumor.

Stage 3:The disease has spread beyond the kidneys to nearby lymph nodes. Surgery man not get rid of the whole cancer.

Stage 4: The disease has spread to other organs like the liver and lungs.

Stage 5: The tumor has affected both kidneys.

Treatment of Wilm’s tumor

Surgery is usually done for people with stage 1 and 2 disease. Here the affected kidney is removed along with lymph nodes. The kidneys and lymph nodes are examined histologically. In some centers, chemotherapy is offered before surgery to shrink the tumor.

If both kidneys are involved your doctors will try to save some part of the kidney. This is because removing both kidneys means the patient is automatically dependent on dialysis.

Chemotherapy agents are drugs that kill cancer cells. They may be given before surgery or after surgery. In people who have metastatic disease chemotherapy is important. Some drugs used for Wilm’s tumor include doxorubicin, vincristine, dactinomycin, cyclophosphamide, and etoposide.

Radiation therapy may be given post-surgery and also in those who have received chemotherapy and surgery.

Follow up

Long-term monitoring is important as the disease can recur. A common site of relapse is the lung. Ultrasonography and CXR are used to monitor patients. The frequency of follow-up depends on the stage of the disease and response to treatment. For example, someone with Stage 1 or 2 disease with favorable histology might be asked to do abdominal ultrasound yearly for the next six years. But someone with stage 3 and favorable histology would be asked to do the abdominal ultrasound six weeks after surgery and then 3 monthly for about 15 months and then 6 monthly for 18 months and thereafter yearly for 2-3 years.

Bottom-line 

Wilm’s tumor is a common cancer seen primarily in children. Treatment consists of surgery with/without chemotherapy or radiation. Survival is good at 4 years after the initial diagnosis. Long-term follow-up is important because the disease can recur.

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