KidsMD Health Topics

Wilms' Tumor

  • If your child has been diagnosed with Wilms’ tumor, you are sure to have many questions and concerns. Learning the basics about the condition will help you to prepare for the journey ahead.

    Wilm’s tumor is a cancerous tumor in the cells of the kidney. It most often starts in the kidneys but, in rare cases, it can occur in other parts of the body. If Wilms’ tumor spreads, it most often moves into the lungs. Fortunately, with the right treatment, Wilms’ tumor is often highly treatable.

    • It’s the most common type of renal (kidney) cancer and accounts for about 6 percent of all childhood cancers.
    • About 500 children in the United States are diagnosed with a Wilms’ tumor each year.
    • Wilm’s tumor can occur at any age between infancy and age 15, but usually is detected by the time a child is 3 years old. Adults rarely have Wilms’ tumor.
    • The tumor can be very large, and it may spread to other body tissues, most often the lungs.
    • With prompt and aggressive treatment, Wilms’ tumor is successfully treated in the majority of affected children with a combination of surgery, and/or chemotherapy and/or radiation therapy. 


    How Dana-Farber/Boston Children’s approaches Wilms’ tumor

    Children with Wilms' Tumor are treated through the Kidney Tumor Program at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, an integrated pediatric oncology program through Dana-Farber Cancer Institute and Boston Children’s Hospital that provides—in one specialized program—all the services of both a leading cancer center and a pediatric hospital.

    Major advancements have occurred in the treatment of Wilm’s tumor over the last two decades, primarily because of studies by the National Wilms' Tumor Study Group, of which Boston Children's Hospital was a member. These studies have rigorously compared treatment regimens to determine the most effective and safest treatments. For example, one study showed that briefer courses of therapy are as effective as longer courses, and less harmful. Children’s Hospital is now an active member of the Boston Children’s Oncology Group (COG).

  • What causes Wilms’ tumor?

    As a parent, you undoubtedly want to know what may have caused your child’s tumor. Most cases of Wilms’ occur by chance with no family history of the disease or other known cause. The tumors can be the result of genetic mutations that affect cell growth in the kidney. These mutations generally arise after birth, but, in some rare cases, children are born with a genetic predisposition to cancer.

    A small percentage of patients with Wilms' tumor have certain rare genetic syndromes such as:

    • hemihypertrophy
    • WAGR syndrome
    • Denys-Drash syndrome
    • Beckwith-Wiedemann syndrome


    What are the symptoms of Wilms' tumor?

    The most common symptom of Wilms’ tumor is the sudden appearance of a non-tender mass in the abdomen.

    Though each child may experience symptoms differently, your child’s symptoms may include the following:

    • swelling of the abdomen
    • blood in the urine
    • abdominal pain
    • decreased appetite
    • weakness or tiredness
    • fever
    • high blood pressure
    • constipation

    Keep in mind that the symptoms of Wilms’ tumor may resemble other, more common conditions or medical problems. Always consult your child's physician for a diagnosis.


    Q: What is the expected outcome after treatment?

    A: With prompt and aggressive treatment, most children with Wilms’ tumor are successfully treated with a combination of surgery, and/or chemotherapy and/or radiation, and experience relatively few side effects from treatment.

    Q: Where will my child be treated?

    A: Children treated through Dana-Farber/Boston Children’s Cancer and Blood Disorders Center receive outpatient care at the Jimmy Fund Clinic on the third floor of the Dana Farber Cancer Institute. If your child needs to be admitted to the hospital, she will stay at Boston Children’s Hospital on the sixth floor of the Berthiaume building.

  • The first step in treating your child is forming an accurate and complete diagnosis. Your child’s physician may recommend a number of different tests to determine the cause of her symptoms. In addition to a complete medical history and physical examination, your child’s doctor may order one or more of the following:

    • Abdominal ultrasound: This imaging test can provide an outline of your child’s kidneys, the tumor, and determine if there are problems in the renal or other major veins in the abdomen. It can also determine if there are any lesions or tumors in the opposite kidney. This is usually the first test we recommend if a tumor is suspected.
    • Chest or abdominal x-ray: An x-ray can help determine the size and location of the tumor and whether it has spread.
    • Chest and abdominal computerized tomography (CT) scan: CT scans provide more detailed images than x-rays.
    • Magnetic resonance imaging (MRI): MRI is used in some cases to look for tumor in blood vessels or other organs.
    • Blood and urine tests: These can evaluate your child’s kidney and liver function and look for any other blood-related abnormalities.
    • Biopsy: In some cases, a biopsy of the tumor helps your child’s doctor determine the tumor type.
    • Surgical removal of the tumor and kidney (nephrectomy): surgery may be needed to make a definitive diagnosis. Surgical resection (removal of a tumor by surgery) is the goal of therapy.

    How is Wilms’ tumor classified?

    An important part of diagnosing Wilms’ tumor involves staging and classifying the disease, which will help your child’s doctor determine treatment options and prognosis. Staging is the process of determining whether the cancer has spread and, if so, how far.

    Kidney tumors are typically categorized into five stages. Wilms’ tumor, the most common type of pediatric kidney tumor, is staged as follows by the Boston Children’s Oncology Group (COG):

    • Stage I: The tumor is limited to the kidney and can be completely removed surgically. About 40 percent of tumors are stage I.
    • Stage II: The tumor extends beyond the kidney but can be completely removed surgically. This includes about 20 percent of tumors.
    • Stage III: The tumor cannot be completely removed surgically or is spilled at surgery, but disease is still limited to the abdomen. About 20 percent of tumors are stage three.
    • Stage IV: The disease has spread from the abdomen through the bloodstream and may be found in the lung, liver, bone, or brain as well as distant lymph nodes. About 10 percent of cases are stage four.
    • Stage V: The tumor is found on both kidneys at the time of diagnosis. This occurs in about 5 percent of cases.

    Your child’s doctor can provide additional information on the classification of Wilms’ tumors.

    After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options.

  • If your child has been diagnosed with a Wilms’ tumor, you’ll naturally be eager to know how your child’s physician will treat the tumor. Your child’s physician will determine a specific course of treatment based on several factors, including:

    • your child's age, overall health and medical history
    • type, location, and size of the tumor
    • extent of the disease
    • your child's tolerance for specific medications, procedures or therapies
    • how your child's doctors expects the disease to progress

    There are a number of treatments we may recommend. Some of them help to treat the tumor, while others are intended to address complications of the disease or side effects of the treatment.

    What are the treatments for Wilms' tumor?

    Treatment will then depend on the extent of spread of your child’s tumor and its stage. Treatment for Wilms’ tumor is based on a comprehensive risk assessment that includes factors such as:

    • your child’s age
    • the size of the tumor
    • microscopic characteristics of the tumor
    • how far the tumor has spread
    • genetic characteristics of the tumor

    The first step in most treatments is surgery to remove the tumor.

    The most common operation is a radical nephrectomy, which removes the whole kidney, the tissue around the kidney, the ureter and the adrenal gland (which sits on top of the kidney). This operation is performed if the tumor has occurred in only one of the kidneys. In some cases, low-stage Wilms’ tumors may be treated with surgery alone.

    If your child has tumors in both kidneys or has a known predisposition to kidney cancer, your child’s physician may recommend a partial nephrectomy or kidney-sparing surgery which aims to remove the tumor while leaving healthy kidney tissue alone.

    In rare cases—when the tumor is too big or has spread too far—your child’s doctor will recommend chemotherapy to try to shrink the tumor before surgery.

    During surgery, a biopsy may need to be done in your child’s other kidney if a suspicious area is found on examination.

    Surgery is followed by chemotherapy and sometimes radiation therapy. The type of chemotherapy and the need for radiation are determined by tumor stage and type. The type of chemotherapy will be determined based on the tumor size, tumor type and the extent of spread of the tumor. Radiation therapy may be indicated for some tumors.

    In very rare cases, a stem cell transplant, involving a transplant of your child’s own stem cells may be used. This allows your child’s physician to give high-intensity chemotherapy in difficult to treat cases of Wilms’ tumor. Stem cell transplantation and the treatment needed to manage its effects are complex and involve some risk. Your physician will give you more detailed information on what to expect.

    How are side effects managed?

    Side effects in the treatment of Wilms’ tumor can arise from surgery, radiation and chemotherapy.

    • Procedures should be performed in specialized centers where experienced surgeons, working in the most technologically advanced settings, can provide the most appropriate kidney surgery.
    • Radiation therapy often produces inflammation, which can temporarily exacerbate symptoms and dysfunction.
    • Some of the chemotherapy agents are associated with fatigue, diarrhea, constipation and headache. These side effects can be effectively managed under most circumstances with standard medical approaches.

    Our cancer treatment center has specialists who deliver complementary or alternative medicines. These treatments, which may help control pain and side effects of therapy include the following:

    • acupuncture/acupressure
    • therapeutic touch
    • massage
    • herbs
    • dietary recommendations

    Talk to your child’s physician about whether complementary or alternative medicine might be a good option for your child.

    Follow-up care

    You and your child’s care team will establish a schedule of regular follow-up care to monitor ongoing response to treatment and possible late effects of treatment, and to evaluate the health of the remaining kidney.

    Long-term outlook

    As with any cancer, prognosis and long-term survival can vary greatly from child to child. Prompt medical attention, aggressive therapy and continued follow-up are important for the best possible prognosis.

    Factors that influence the outlook for a child with Wilms’ tumor include:

    • extent of the disease
    • the histology of the tumor (what it looks like under the microscope)
    • genetic changes in the tumor
    • age and overall health of the child at diagnosis
    • size of the primary tumor
    • response to therapy
    • your child's tolerance of specific medications, procedures or therapies

    With the appropriate therapy, which may include surgery, chemotherapy and/or radiation, the overall prognosis for children with Wilms’ tumor is excellent. More aggressive tumors or tumors that have spread significantly may be harder to treat.

    The goal of treatment of Wilms’ tumor is both to cure the cancer and to minimize the long-term effects of therapy. Therefore, patients are carefully assessed so that they receive the appropriate amount of therapy with minimal side effects.

  • Researchers at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center's Kidney Tumor Program conduct laboratory and clinical research designed to improve understanding and treatment of pediatric kidney tumors. We offer clinical trials through the Children’s Oncology Group. Here are some of the things we’ve been working on:

    • Identifying the best treatment for Wilms’ tumor
      Major advancements have occurred in treatment of Wilms’ tumor over the last two decades, primarily because of studies by the National Wilms' Tumor Study Group, of which Boston Children's Hospital was a member. These studies have rigorously compared treatment regimens, and helped define the right treatment for each stage and type of Wilms tumor. In one large study, it was shown for low-stage Wilms tumor that briefer courses of therapy were safer and as effective as longer courses.

    • Risk-stratifying treatment of children with bilateral tumors
      The traditional treatment for pediatric kidney tumors is a two-step process: Surgeons remove as much of the tumor as possible, then oncologists use chemotherapy to kill remaining cancerous cells. If the tumor is bilateral, appearing in both kidneys, chemotherapy is sometimes also used before surgery to reduce the size of the tumor. Our researchers are investigating the use of continuous pathological review throughout treatment to evaluate the best therapeutic approach for bilateral pediatric kidney tumors.

    • Searching for markers
      Researchers are conducting studies to better understand how to diagnose and treat renal tumors. For example, researchers at our center are investigating whether kidney tumors emit markers in a child’s urine. If discovered, these markers could be used to screen for early recurrence of relapsed cancers. They may also help clinicians screen types of tumors up front, so treatments are personalized to the exact make up of a child’s tumor.

    • Treating rhabdoid tumors

      Elizabeth Mullen, MD, director of the Kidney Tumor Program, is involved in a Boston Children’s Oncology Group working group for rhabdoid tumors that reaches across disease groups (brain and spinal tumors, kidney tumors and rare tumors) and disciplines. Although rhabdoid tumors were once thought to be a type of Wilms’ tumor, they are now considered to be a separate category altogether. This national initiative is being led by Susan Chi, MD, from our Pediatric Brain Tumor and Carlos Rodriguez-Galindo, MD from our Bone and Soft Tissue Tumor Program. Dr Charles Roberts, MD, PhD, is Boston Children’s lead investigator in basic science research in the area of rhabdoid tumors.

    Clinical trials

    For many children with rare or hard-to-treat conditions, clinical trials provide new options.

The future of pediatrics will be forged by thinking differently, breaking paradigms and joining together in a shared vision of tackling the toughest challenges before us.”
- Sandra L. Fenwick, President and CEO