What is Wilms’ tumor?
Wilms’ tumor is a rare type of kidney cancer that primarily
affects children. Less than one in every 10,000 children is affected by
Wilms’ tumor in the United States. Roughly 500 children are newly diagnosed each year.
Although rare, Wilms’ tumor is the most common type of kidney cancer in
children, and the fourth most common type of childhood cancer
Cancer occurs when abnormal cells in your body multiply
uncontrollably. This can happen at any age, but some cancers are unique to
childhood. Wilms’ tumor, also known as nephroblastoma, is one such cancer.
Wilms’ tumor is typically diagnosed in children around 3
years of age. It’s rarely seen or diagnosed after age 8, but it can occur in
older children and adults.
What are the signs and symptoms of Wilms’ tumor?
The condition most often occurs in children with an average
age of 3 to 4 years. Symptoms of Wilms’ tumor are similar to those of other
childhood ailments, so it’s important to see your doctor for an accurate
diagnosis. Children with Wilms’ tumor might display the following symptoms:
- abdominal pain, swelling, or discomfort
- nausea and vomiting
- weakness and fatigue
- loss of appetite
- blood in their urine or discoloration of their
- high blood pressure, which may cause chest pain,
shortness of breath, and headaches
- increased and uneven growth of one side of their
Causes and risk factors for Wilms’ tumor
It’s not clear what exactly causes Wilms’ tumors. So far,
researchers haven’t found any clear links between Wilms’ tumor and
environmental factors. These factors include drugs, chemicals, or infectious
either during a mother’s pregnancy or after birth.
Researchers don’t think children directly inherit the
condition from their parents. Only one to two percent of children with Wilms’ tumors
have a relative who has had the same condition. That relative typically isn’t a
However, researchers believe certain genetic factors might
increase a child’s risk, or predispose children to developing Wilms’ tumor.
The following genetic syndromes may increase a child’s risk
for Wilms’ tumor:
- Beckwith-Wiedemann syndrome
- WAGR syndrome
- Denys-Drash syndrome
- Frasier syndrome
- Perlman syndrome
- Sotos syndrome
- Simpson-Golabi-Behmel syndrome
- Bloom syndrome
- Li-Fraumeni syndrome
- Trisomy 18, also called Edward’s Syndrome
Frasier syndrome, WAGR syndrome, and Denys-Drash syndrome
are linked to changes or mutations in the WT1
gene. Beckwith-Wiedemann syndrome, a growth disorder that causes body and organ
enlargement, is linked to a mutation in the WT2
These are both genes that suppress tumors and are found on
chromosome 11. However, changes in these genes only account for a small
percentage of Wilms’ tumors. There are likely other gene mutations that haven’t
yet been discovered.
Many children with Wilms’ tumor also have birth defects. The
following birth defects are associated with the condition:
- aniridia: a missing or partially missing iris
- hemihypertrophy: when one side of the body is
larger than the other
- cryptorchidism: undescended testicles in boys
- hypospadias: when the urinary opening is on the
underside of the penis
Wilms’ tumor occurs slightly more often in African-American
children than in white children. It’s least common in Asian-American children.
The risk for
development of Wilms’ tumor is equal in males and females, although boys may
develop it at a younger age.
How is Wilms’ tumor diagnosed and staged?
Children who have any syndromes or birth defects linked to
Wilms’ tumor should be screened for the disease. These children should have a
physical exam and an ultrasound on a regular basis. The ultrasound will look
for any kidney tumors before the tumor spreads to other organs.
According to the American Cancer Society, doctors recommend that
children with a higher risk of Wilms’ tumor get an exam every three or four
months until they’re about 8 years old. Talk to your doctor if you have any
family members who have had Wilms’ tumor. If you do, your doctor may recommend
that all children in your family have regular ultrasound tests.
The condition is extremely rare in children who don’t have
any risk factors. Therefore, tests for Wilms’ tumor aren’t typically done
unless a child has symptoms, such as swelling in the abdomen.
To confirm a diagnosis of Wilms’ tumor, your doctor may
order diagnostic tests, including:
- blood or urine tests
- complete blood count (CBC)
- abdominal X-ray or ultrasound
- CT scan
These tests will help your doctor make an accurate
diagnosis. Once diagnosed, more tests will be done to determine how advanced
the disease is. Treatment and outlook will depend on the stage of your child’s
Wilms’ tumor has five stages:
The tumor is contained within one kidney and can be completely removed with
surgery. About 40 to 45 percent of Wilms’ tumors are stage 1.
The tumor has spread into the tissue and vessels around the kidney, but it can
still be completely removed with surgery. About 20 percent of Wilms’ tumors are stage 2.
The tumor can’t be completely removed with surgery, and some cancer remains in
the abdomen. About 20 to 25 percent of Wilms’ tumors are stage 3.
The cancer has spread to faraway organs, such as the lungs, liver, or brain.
About 10 percent of Wilms’ tumors are stage 4.
The tumor is in both kidneys at the time of diagnosis. About 5 percent of Wilms’ tumors are stage 5.
Wilms’ tumors can also be classified by looking at the tumor
cells under a microscope. This process is called histology.
These types of tumors have a nucleus in the cells that looks
very large and distorted. This is referred to as anaplasia. The more anaplasia,
the harder the tumor is to cure.
This means that there is no anaplasia. Over 90 percent of Wilms’ tumors have favorable
histology. This means most tumors are easier to cure.
Treatment for Wilms’ tumor
Since this type of cancer is so rare, children with Wilms’
tumors are usually treated by a team of doctors, including:
- urologists or urinary tract specialists
- oncologists, or cancer specialists
The team of doctors will come up with a treatment plan for
your child. Be sure to discuss all options available for your child as well as
their possible side effects.
The main types of treatment are:
- radiation therapy
Most children undergo a combination of treatments. Surgery
is usually the first treatment used for people in the United States. The goal
of surgery is to remove the tumor. In some cases, the tumor can’t be removed
because it’s too big, or the cancer may have spread to both kidneys or into the
blood vessels. If so, your doctors might first use chemotherapy or radiation
therapy (or both) to try to shrink the tumor before surgery.
Your child might have to undergo more chemotherapy,
radiation therapy, or surgery if the tumor isn’t completely removed the first
time. The specific drugs and the extent of the treatment prescribed will vary
depending on your child’s condition.
Clinical trials are research studies that test out new
treatments or procedures. They are a great way for doctors and people to learn
better methods to treat cancer, especially rare cancers. Ask your doctor if a
local hospital conducts clinical trials to see if you qualify.
Complications from Wilms’ tumor
As with any cancer, the spreading of the disease to other
organs, or metastasis, is a potentially serious complication. If your child’s
cancer spreads to distant organs, it will require more aggressive treatment.
Depending on the drugs used for chemotherapy, your child may
also experience unpleasant side effects. These vary from child to child but may
- hair loss
- nausea and vomiting
- loss of appetite
- weight loss
- mouth sores
- sleep problems
- bladder issues
- skin and nail changes
- increased risk of infection
Talk to your doctor about what to expect during and after
your child’s treatment. Your doctor may prescribe additional medications to
deal with the side effects of treatment. Hair will normally grow back within a
few months after treatment is completed.
High blood pressure and kidney damage can occur as a result
of your child’s tumor or its treatment. For this reason, follow-up care is just
as important as the initial treatment. Follow-up care may include physical
exams and imaging tests to make sure the tumor hasn’t come back. It may also
include blood and urine tests to check how the kidneys are working. Ask your
child’s doctor about long-term complications and how to look out for these
Long-term outlook for Wilms’ tumor
About 90 percent of children with Wilms’ tumor are
cured. The exact survival rate depends on the stage and histology of the tumor.
The outlook for children with unfavorable histology is much worse than for
children with favorable histology.
The four-year survival rates by tumor stage and
histology are as follows:
Stage 1: 99 percent
Stage 2: 98 percent
Stage 3: 94 percent
Stage 4: 86 percent
Stage 5: 87 percent
Stage 1: 83 percent
Stage 2: 81 percent
Stage 3: 72 percent
Stage 4: 38 percent
Stage 5: 55 percent
Can Wilms’ tumor be prevented?
Wilms’ tumor can’t be prevented. Children with a family
history of the condition or risk factors, such as birth defects or syndromes, should
have frequent kidney ultrasounds. These screening tools can ensure early
Coping and support
Talk with your child’s team of doctors and specialists for
information and support. They can point you in the direction of other support
resources available to you while your child goes through treatment. These
resources can include:
- social work services
- support groups (online or in person)
- financial aid
- advice on nutrition and diet
Ask to speak to parents who have already gone through
treatment for Wilms’ tumor. They can provide additional support and
You can also contact the American Cancer Society’s National
Cancer Information Center at 800-227-2345. They have specialists on-call every
day, 24 hours a day, to help you and your child during and after treatment.
Your child will be going through a lot during this time. You
can make things a little bit easier for them by trying the following
- stay with your child during treatment
- bring a favorite toy or book with you to the
- make time for play while in the hospital, but
make sure your child is getting adequate rest
- make sure your child is eating and drinking
- prepare your child’s favorite foods and increase
their intake of nutritional fluids if their appetite is low
- keep a journal or record of how your child is
feeling at home so you can share it with your doctor
- discuss the disease with your child in terms
they can understand and encourage your child to share their feelings
- try to make life as normal as possible for them