Wilms tumor in children

Wilms tumor is the most common kidney cancer in children. Most affected children have a tumor in one kidney, but about 5% have a tumor in both kidneys.

The causes are unclear, but most often it affects children between the ages of 3 and 4 years. It is much less common after 5 years. Doctors are getting better at detecting and treating this type of cancer, so many children who get it make a full recovery.

Symptoms of Wilms tumor

Some children with Wilms tumor do not notice any symptoms. Others may have:

Belly pain
Swelling in their belly
A growth that you can see or feel in their belly
Fever
Nausea
Lack of appetite
High blood pressure
Blood in their pee
Constipation
Shortness of breath

Many Wilms tumors become very large before they are noticed. Sometimes they are the only sign of illness.

Causes of Wilms tumor

All types of cancer occur when the cells in your body begin to grow out of control. If your child has Wilms tumor, his kidney cells have not grown properly. Instead, they turned into cancer cells. In most cases, this is due to an accidental change in a gene. In rare cases, this is due to genetic changes passed down from parents.

Risk factors for Wilms tumor

Things that can make a child more prone to Wilms tumor include:

Age. Most children who get this type of cancer are between the ages of 3 and 5.

Gender. It occurs more frequently in girls than in boys.

Ethnicity. Black children are slightly more likely to develop Wilms tumor than children of other races.

History of the family. If a member of your family has had Wilms' tumor, chances are your child will have it too.

Congenital malformations. These may include:

Testicles that haven’t dropped (cryptorchidism)
The opening of the penis is on the underside instead of on the tip (hypospadias)
A total or partial lack of the colored area of the eye (aniridia)
An oversized arm or leg (hemihyphertrophy)

Another health problem. Wilms tumor sometimes occurs in children with other rare diseases:

Wilms tumor, aniridia, genitourinary anomalies and mental retardation syndrome causes problems in the urinary tract.
Boys with Denys-Drash syndrome have testicles but also have female traits.
Microcephaly is when a baby is born with an unusually small head.
Beckwith-Wiedemann syndrome causes internal organs that are larger than usual.

Types of Wilms tumors

There are two types of Wilms tumors, distinguished by how the cells look under a microscope.

Favorable histology. More than 9 out of 10 Wilms tumors fall into this group. This means that there is not much difference between cancer cells. Children with this type have a good chance of being cured.
Unfavorable or anaplastic histology. This type has many deformed cancer cells. The cure can be much more difficult.

Diagnosis of Wilms tumor

Your child's medical appointment will likely include:

Physical examination and medical history. Your doctor will ask you about your symptoms and if you have a family history of cancer or urinary tract problems.
Blood test to check the proper functioning of your child's kidneys and liver, red and white blood cells and blood clotting.
Urinalysis to look for blood
Imaging tests such as an ultrasound, magnetic resonance imaging, or CT scan of your child's abdomen

If the doctor finds a tumor in your child's kidney, they may:

Take a small sample for examination under a microscope (biopsy)
Order additional imaging tests to see if the disease has spread
Do a bone scan to find the diseased bone

Staging Wilms tumor

Your doctor will use the results of the test to determine how far the tumor has spread. This is called staging. Wilms tumor stages:

Stage I. It’s in only one kidney. Surgery can remove it all.
Stage II. Cancer has moved into the area around the kidney, but surgery can remove it all.
Stage III. Cancer hasn’t spread outside the child’s abdomen. Surgery can’t remove it all.
Stage IV. Cancer has spread to parts of the body that are farther away, like the lungs, bones, or brain, or to lymph nodes outside the belly.
Stage V. There are tumors in both kidneys.

Treatment of Wilms tumor

Treatment for Wilms tumor depends on how far the cancer has spread. This may include surgery, chemotherapy, and radiation therapy.

Surgery

If your doctor is operating, they may perform one of the following procedures:

Partial nephrectomy. This removes the tumor and some of the healthy tissue around it.
Radical nephrectomy. At the same time, the affected kidney, the ureter (the tube through which urine is drained from the kidney), the adrenal gland above the kidney and surrounding tissues are removed.
Removal of both kidneys. In some cases, the doctor will need to remove both kidneys. Your child will then need to undergo dialysis using a machine to filter waste from the blood. Once they are healthy enough, they can be given a kidney transplant.

Chemotherapy

Some medicines can fight or kill cancer cells in your child's body. Most children with Wilms tumor will receive chemotherapy at some point in their treatment. These drugs can also affect healthy cells, causing side effects including:

Hair loss
Fatigue
Mouth sores
Loss of appetite
Nausea and vomiting
Diarrhea or constipation
Bruising or bleeding easier than usual
Higher chances of infection

Your healthcare team will often be able to manage the side effects.

Radiation

Strong radiation can also kill cancer cells. The machine focuses it on the cancer.

Doctors tend to use radiation therapy for stage III tumors and above. But it can also have short and long term side effects, including tissue damage, so they will use as little as possible.

The prognosis for most children with Wilms tumor is good. Up to 90% of children with a tumor with favorable histology can be cured. If the tumor has an unfavorable histology, the cure rate is lower.

After cancer treatment is completed, your child will see the doctor regularly to make sure he stays healthy.

If there is anything you don't understand, be sure to ask your doctor. This will help you learn how best to support your child.