Solid tumors
Wilms tumor
If you or someone you love has just heard this diagnosis, start here. This guide explains what the condition is, how it is usually treated and whether a transplant plays any part.
Wilms tumor is a kidney cancer of young children, and most children with it are cured. Treatment combines surgery and chemotherapy, with radiation for some children. A stem cell transplant is rarely used. It has been tried for some tumors that come back after strong treatment, using the child’s own stored cells, so no donor is involved.
Other names and abbreviations
nephroblastoma, WT, Nephroblastoma
In short
- Wilms tumor is a kidney cancer of young children. Some children have an underlying genetic risk that makes it more likely.
- Treatment combines surgery and chemotherapy, with radiation for some risk groups. Tumors that come back may get different treatment or a clinical trial.
- High-dose chemotherapy with a return of the child's own stem cells has been used for some high-risk tumors that come back. It is not routine, and it uses no donor.
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Underlined words open a short explanation. See all terms
Where transplant fits
High-dose chemotherapyVery strong drug treatment given in large doses, often to kill cancer cells. It also destroys the bone marrow and can cause other serious side effects. A stem cell transplant usually follows to rebuild the marrow. with autologous stem cell rescueComing from the patient's own body. In an autologous transplant, the patient's own stem cells are collected and stored, then given back after high-dose treatment. It does not use a donor. has been used for selected high-risk relapsesWhen a disease comes back after a period of getting better. Relapsed disease has returned after treatment helped for a time.. The evidence is mainly nonrandomized and does not make transplantA treatment that gives a patient healthy blood-forming stem cells through a vein. The cells travel to the bone marrow and replace faulty marrow or marrow damaged by treatment. They can come from the patient or a donor. routine for all Wilms tumors. Rescue uses the child’s cells, not a registry donor.
Treatment depends on the exact diagnosis, disease stage, prior treatment and the person’s health.
Key facts
- Who it affects
- Wilms tumor mainly affects young children.
- How common
- About 9.7 per 1 million children younger than 15 each year (about 650 children a year in the U.S.)United States, NCI National Childhood Cancer Registry data, as reported in NCI PDQ (updated April 2025); much lower in Asian populations Source: How common
- Cells used in a transplant
- The patient’s own collected blood-forming cells for autologous stem cell rescue, when that procedure is appropriate.
- Where a donor fits
- Limited transplant role
The condition
What it is
Wilms tumor, also called nephroblastoma, is the most common kidney cancer in infants and children. It usually affects one kidney. About 5 to 10 in every 100 children with Wilms tumor have more than one tumor, in one or both kidneys.
Most children are diagnosed between ages 2 and 5, and nearly all before age 10. Wilms tumor in older teens and adults is rare.
Under a microscope, most Wilms tumors have what doctors call favorable histology. About 1 in 10 has anaplastic histology, where the cells look very abnormal. Anaplastic tumors are harder to treat with chemotherapy. Histology is one of the most important things that shapes a child’s treatment.
About these numbers. Each one says which group of people it comes from, and the place and years where the source gives them. It describes what happened across that group, not what will happen to any one person. And a figure measured among people who had a transplant is not the same as the number of people who need one.
- 44 monthsAverage age at diagnosis, one kidney
Children with Wilms tumor in one kidney, as reported by the U.S. National Cancer Institute (PDQ, updated April 2025); the average was 31 months when both kidneys were affected
Read the source: Average age at diagnosis, one kidney
What causes it
Wilms tumor starts when kidney cells change in the way they grow and divide. The exact cause is often unknown. Many Wilms tumors are thought to grow from small groups of immature kidney cells, left over from before birth, that never finished developing. These leftover cells are called nephrogenic rests.
About 9 in 10 Wilms tumors come from gene changes that happen only in the tumor. They are not passed down in families. About 1 in 10 are linked to a gene change present in all of the body’s cells. Some of these children have a genetic syndrome, such as WAGR syndrome, Denys-Drash syndrome or Beckwith-Wiedemann syndrome. Others have signs such as aniridia, where part or all of the colored part of the eye is missing. Another sign is one side of the body growing larger than the other (hemihypertrophy).
Wilms tumor rarely runs in families. Only about 2 in 100 children with it have a relative who also had it. A brother or sister of a child with Wilms tumor has less than a 1% chance of getting it.
Symptoms and effects
Some children have no symptoms at first. Often a parent notices a lump in the belly, or that the belly looks bigger than before. Sometimes a doctor finds the tumor at a routine checkup. Other signs include belly pain, blood in the urine, high blood pressure, fever with no known cause, and loss of appetite or weight.
About 15% to 20% of children already have spread when they are diagnosed. The lungs are the most common place, followed by the liver. Spread to the lungs can cause a cough, trouble breathing or chest pain.
The tumor can grow into the large vein that carries blood from the kidney toward the heart, which changes how surgery is planned. About 4% of children also have a bleeding problem called acquired von Willebrand disease, often without symptoms. It usually goes away once chemotherapy starts or the tumor is removed.
A simple drawing of a body. Often affected: kidneys. Can also be affected: airway and lungs, liver and blood vessels.
Often affected
- Kidneys: usually one kidney
Can also be affected
- Airway and lungs: the most common place it spreads
- Liver
- Blood vessels: the large vein that carries blood from the kidney toward the heart
Both kidneys are shaded, but Wilms tumor usually affects one. Most children have only some of these, and the drawing says nothing about how severe any of them will be.
Diagnosis and treatment
How Wilms tumor is diagnosed
The doctor asks about symptoms and family history and examines the child. The first scan is usually an ultrasound of the belly. CT or MRI scans then show the tumor, whether it has grown into nearby blood vessels, and whether the other kidney is affected. A CT scan of the chest checks for spread to the lungs. Blood and urine tests check blood counts and how the kidneys and liver are working.
A needle biopsy is often not done first. If the tumor can be removed, cutting into it beforehand could spread tumor cells and would raise the stage. So in North America the diagnosis is usually confirmed when the removed kidney is examined. In Europe, chemotherapy starts first and the tumor is examined after surgery. A biopsy may be done when the tumor looks unusual on scans or cannot be removed safely at first.
The pathologist decides whether the histology is favorable or anaplastic. Lab tests on the tumor add detail about risk. They look for changes such as extra copies of part of chromosome 1 (1q gain) or missing parts of chromosomes 1 and 16 (1p and 16q). Stages run from I to IV, and stage V means tumors in both kidneys. A genetics referral is usually suggested when a child has a family history of cancer, tumors in both kidneys, or signs of a related syndrome.
Some children are known to have a higher risk, such as many with Beckwith-Wiedemann syndrome, WAGR syndrome or certain forms of aniridia. They usually have regular belly ultrasounds, often every 3 months, until at least age 8. The goal is to find a tumor while it is small.
How it is treated
A pediatric oncologist (a children’s cancer doctor) leads the team. Treatment depends on the stage, the histology, the child’s age and whether one or both kidneys are affected. There are two standard approaches. In North America, most children have surgery first to remove the affected kidney and nearby lymph nodes (nephrectomy), then chemotherapy. In Europe, the SIOP group gives chemotherapy first to shrink the tumor, then surgery. Both groups operate first on babies younger than 6 months.
The main chemotherapy drugs are vincristine and dactinomycin. Doxorubicin is added for higher-stage tumors and for some tumors with high-risk features. Some children younger than 2 with a small stage I tumor that has favorable histology need surgery only. Radiation is added for some higher-stage or anaplastic tumors and for spread to places such as the lungs.
When both kidneys are affected, chemotherapy usually comes first. Then surgeons remove the tumors while saving as much healthy kidney as they can (partial nephrectomy).
About 15% of children with favorable-histology tumors, and about half with anaplastic tumors, have the cancer come back. Treatment then depends on what the child had before. Children who had only vincristine, dactinomycin or both usually receive more chemotherapy, surgery and radiation, and many are cured. For tumors that come back after stronger treatment, high-dose chemotherapy followed by the child’s own stem cellsYoung cells that can grow into every type of blood cell: red cells that carry oxygen, white cells that fight infection and platelets that help blood clot. They are found in the bone marrow and the bloodstream. (autologous stem cell rescue) has been used.
The benefit of this rescue is not proven. No randomized trial has compared it with standard chemotherapy, and attempts to run one have failed. European transplant experts (EBMT, 2025) class it as developmental, which means more trialsA research study that tests how well a new medical approach works in people. Trials can test new ways to screen for, prevent, diagnose or treat a disease. are needed. In an analysis by the European SIOP renal tumor study group, adding it did not improve results for children whose tumor came back after only vincristine and dactinomycin.
- 45%Alive 5 years after high-dose chemotherapy with own stem cells
253 patients with Wilms tumor that had come back, treated in 1990–2013 and reported to the CIBMTR, an international transplant registry (published 2017). The cancer coming back caused 81% of deaths.
Read the source: Alive 5 years after high-dose chemotherapy with own stem cells
A transplant is not part of first treatment for Wilms tumor, and most children never need one.
Kinds of treatment described for Wilms tumor: medicines, surgery or radiation and a transplant with the person’s own cells (for a few people).
After diagnosis, the options described here
Medicines
Chemotherapy comes after surgery in North America, while in Europe it comes first to shrink the tumor.
Surgery or radiation
Surgery removes the tumor, often with the whole kidney, and radiation is added for some children.
Transplant with the person’s own cells, For a few people
It has been tried for some tumors that come back after strong treatment, using the child’s own stored cells, but its benefit is not proven.
These are the kinds of treatment this page describes, not a plan. Which ones fit, in what order and whether they are combined differs from person to person.
Daily life and the donor’s role
Living with the condition
Hearing that a young child has cancer is frightening. Alongside the doctors, a child’s care team often includes pediatric nurse specialists, social workers, psychologists, child life specialists and rehabilitation specialists. A fertility specialist may join too. Chemotherapy for Wilms tumor is given through a vein.
Most children live with one kidney after surgery. Because most children are cured, follow-up continues into adult life. A large U.S. study followed adults who had Wilms tumor in one kidney as children. By 35 years after diagnosis, 34% had a serious long-term health problem, compared with 15% of their brothers and sisters. Risks were lowest after vincristine and dactinomycin alone, and higher after doxorubicin or radiation.
Late effects can include heart problems after doxorubicin, a second cancer, bowel blockage, and fertility or pregnancy problems after radiation to the belly. In the same study, 2.4% developed kidney failure. No single drug or radiation dose explained it, which suggests losing a kidney may be the main cause. Children with WAGR syndrome or other WT1 gene changes, and children who had tumors in both kidneys, usually have kidney function and blood pressure checked for life.
For the few children who have high-dose chemotherapy with stem cell rescue, stem cells are first collected from the child’s blood or bone marrowThe soft, spongy tissue in the center of most bones. Red bone marrow holds the blood-forming stem cells that make red blood cells, white blood cells and platelets. and frozen. After the chemotherapy, they are thawed and given back through a vein, where they grow into new blood cells.
The donor’s role
No donor is involved in treating Wilms tumor. Surgery, chemotherapy and radiation use no one else’s cells. When high-dose chemotherapy with stem cell rescue is used, the stem cells are the child’s own. Brothers and sisters do not need to be tested as donors.
A donor stem cell (allogeneicComing from another person. In an allogeneic, or donor, transplant, the stem cells come from a relative or an unrelated volunteer whose cells are a close enough match to the patient's.) transplant is not a standard treatment for Wilms tumor. EBMT’s 2025 recommendations for children list it as generally not recommended, even when the tumor has come back.
This is different from a kidney transplant. A child whose kidneys stop working, most often after tumors in both kidneys, may one day need a donated kidney. Care teams usually wait until 1 to 2 years after treatment ends, with no signs of cancer.
So joining a blood stem cell registry does not help a child with Wilms tumor directly. Registries serve patients with leukemia, lymphoma and other blood disorders, where an unrelated volunteer may be the only possible donor.
Looking ahead
Looking ahead
Outlook for Wilms tumor
Most children with Wilms tumor are cured. Since the 1980s, more than 90% of children with favorable-histology Wilms tumor have been alive 5 years after diagnosis. For children and teens younger than 20 in the United States, 5-year relative survival is 93%.
The outlook is harder for anaplastic tumors, for tumors that come back, and for teens and adults. About 15% of favorable-histology tumors and about half of anaplastic tumors come back, and about 95% of first relapses happen within 2 years. What happens next depends on the earlier treatment. Children with a favorable-histology tumor that comes back after only vincristine, dactinomycin or both have event-free survival of about 70% to 80%. Survival is about 40% to 50% when it comes back after three or more drugs, and about 10% when a relapsed tumor is anaplastic or blastemal-predominant.
In U.S. registry data, teens and young adults aged 15 to 39 with Wilms tumor had lower 5-year overall survival than children: 69%, compared with 94%.
About these numbers. They describe groups of people, not what will happen to any one person.
- 93%Alive 5 years after diagnosis
Children and teens younger than 20 with Wilms tumor in the United States; relative survival from NCI’s National Childhood Cancer Registry data, as reported in NCI PDQ (updated April 2025)
Read the source: Alive 5 years after diagnosis - About 15% (favorable histology); about 50% (anaplastic)Tumor came back after first treatment
Children with Wilms tumor, as summarized by NCI PDQ (updated April 2025)
Read the source: Tumor came back after first treatment - About 40% to 50%Survival after a relapse following three or more drugs
Children with favorable-histology Wilms tumor that came back after treatment with three or more chemotherapy drugs (the high-risk relapse group, 45% to 50% of relapses), as summarized by NCI PDQ (updated April 2025)
Read the source: Survival after a relapse following three or more drugs
These figures describe groups of children, many treated years ago. They cannot predict what will happen to any one child.
Common questions
Is Wilms tumor curable?
Yes, for most children. The U.S. National Cancer Institute says Wilms tumor is curable in most affected children. Since the 1980s, more than 90% of children with favorable-histology Wilms tumor have been alive 5 years after diagnosis. The outlook is harder for anaplastic tumors and for tumors that come back. The outlook section on this page gives the figures, with the groups they describe. No number can predict what will happen to one child.
Is Wilms tumor hereditary?
Usually not. About 9 in 10 Wilms tumors come from gene changes that happen only in the tumor. About 1 in 10 are linked to a gene change present in the whole body, often as part of a syndrome such as WAGR, Denys-Drash or Beckwith-Wiedemann syndrome. Most of these changes are new in the child rather than passed down from a parent. Only about 2% of children with Wilms tumor have a relative who had it, and brothers and sisters have less than a 1% chance of getting it.
How does losing a kidney affect a child later in life?
Serious kidney problems are uncommon after losing one kidney, but they do happen, so kidney checks continue into adult life. In a large U.S. study of adults treated as children for Wilms tumor in one kidney, 2.4% had kidney failure by 35 years after diagnosis. That was about 10 times the rate in their brothers and sisters, and losing a kidney may be the main cause. End-stage kidney disease affects fewer than 1% of children with a tumor in one kidney. It affects about 12% of those with tumors in both kidneys and no related syndrome.
Will my child need a bone marrow or stem cell transplant?
Very likely not. Transplant is not part of first treatment for Wilms tumor. Some tumors that come back after strong treatment have been treated with high-dose chemotherapy, followed by a return of the child’s own stored stem cells. Its benefit has not been proven in a randomized trial. No donor is needed for it. A donor stem cell transplant is generally not recommended for Wilms tumor. A kidney transplant is a separate thing, sometimes needed after tumors in both kidneys.
What is the difference between favorable and anaplastic histology?
Histology means how the tumor cells look under a microscope. Most Wilms tumors have favorable histology. They respond well to chemotherapy and radiation and have a better outlook. About 1 in 10 have anaplastic histology, where the cells divide quickly and look very different from normal kidney cells. Anaplastic tumors are harder to treat with chemotherapy, so children with them usually get stronger treatment, often with radiation. Histology is one of the most important factors in planning care.
Why do some children get chemotherapy before surgery?
There are two standard approaches. In North America, most children have the kidney removed first, which gives an early, exact diagnosis and stage. In Europe, the SIOP group gives chemotherapy first. This shrinks the tumor, lowers the chance it breaks open during surgery, and leads to fewer stage III tumors. In both regions, chemotherapy usually comes first when both kidneys are affected. It also comes first when the tumor has grown far up the large vein toward the heart, or cannot be removed safely at first. The same is true when spread to the lungs causes breathing trouble.
For your next appointment
Wilms tumor
From the Jada Bascom Foundation disease library, jadabascomfoundation.org. Printed .
Questions to bring to your care team
- What stage is my child’s tumor, and is it favorable or anaplastic histology? Was it tested for 1q gain or loss of 1p and 16q?
- Should our family see a genetic counselor, and does my child need ultrasound checks of the other kidney after treatment?
- Which late effects should we watch for, such as kidney function, blood pressure, heart health and fertility, and who will follow my child as an adult?
- If the tumor comes back, which relapse risk group would my child be in? Would a clinical trial or high-dose chemotherapy with my child’s own stem cells be considered?
- What is the goal of each treatment you are suggesting?
- What would make a transplant worth considering later on?
- Where can our family find support during treatment?
A one-page list to take to the next appointment, with room for notes.
Supporting someone with a diagnosisSupport for patients and families
These independent organizations offer information and support. JBF is not affiliated with them.
- Wilms Cancer Foundation Free Wilms tumor information, a parent and caregiver discussion group, a video library and a patient program for children with Wilms tumor.Worldwide (based in Canada and the United States)
- Childhood Cancer International Global network of childhood cancer parent and survivor groups; its member directory helps families find support in their own country.Worldwide
- American Childhood Cancer Organization Emotional and financial support, online peer support, information and bereavement services for families of children and teens with cancer.United States
Sources and further reading
- Wilms Tumor and Other Childhood Kidney Tumors Treatment (PDQ)
NCI, Accessed 2026-09-05 - Indications for haematopoietic cell transplantation and CAR-T: 2025 EBMT practice recommendations
EBMT / Bone Marrow Transplantation, Accessed 2026-09-05 - Stem Cell and Bone Marrow Transplants for Cancer
NCI, Accessed 2026-09-05 - Wilms Tumor (PDQ®)–Patient Version
NCI (PDQ, patient version), Updated 2025-05-12; accessed 2026-09-26 - Wilms tumor
MedlinePlus Genetics, U.S. National Library of Medicine, Last updated 2023-07-13; accessed 2026-09-26 - Wilms Tumor
Boston Children's Hospital, Accessed 2026-09-26 - Outcomes following autologous hematopoietic stem cell transplant for patients with relapsed Wilms' tumor: a CIBMTR retrospective analysis
CIBMTR / Bone Marrow Transplantation (Malogolowkin et al.), 2017-11; accessed 2026-09-26
This information explains a condition and its treatments. It cannot diagnose an illness or recommend treatment for an individual. Your care team can explain how the evidence applies to you. Written and source-checked by the Jada Bascom Foundation. Each page lists the published sources it draws on.
Ways to help
Help another family understand.
Most people with Wilms tumor are treated without a registry donor. A clear explanation can help the next family who hears this diagnosis, and many people with other blood cancers and blood disorders need a donor who is a stranger.
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