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Wilms’ tumor / Nephroblastoma

Wilms Tumor Overview

Wilms tumor is the most common type of kidney cancer in children, and a multidisciplinary approach to treatment is often required. When treated promptly and aggressively, the treatment for Wilms tumor is usually successful. At Sheba Medical Center in Israel, our pediatric specialists are skilled and experienced in treating this disease. We will use precise diagnostics to categorize and stage Wilms tumor quickly, and we will custom-design your child’s cancer treatment with the latest research-based therapies. Our doctors are involved in many cutting-edge research to explore new therapies for Wilms tumors, and we bring this expertise to caring for each individual child.

When treating our young patients, we apply a compassionate bedside manner and holistic approach to medicine. Your child’s overall well-being is essential to planning an efficient, pain-free, and integrative treatment program. Cancer can have devastating effects on you and your child’s quality of life. In addition to offering progressive medical therapies from a range of Sheba’s hospital divisions and specialties, we also offer a variety of supportive services to provide for both your emotional and physical needs.

Wilms' tumor / Nephroblastoma

About Wilms Tumors

Wilms tumors, also called Wilms’ tumor or nephroblastoma, typically occur in young children between 3 to 5 years old, and the incidence of these tumors decreases as kids grow older; Wilms tumors are very rare in adults. Each year, approximately 500 to 600 new cases of Wilms tumor are diagnosed in the United States, and an estimated 6% of all pediatric cancers are Wilms tumors.

What are Wilms tumors?

Wilms tumor is a kind of childhood cancer that begins in the kidneys, and it accounts for about 9 of 10 kidney cancers in children. The majority of Wilms tumors are unilateral, meaning that only one kidney is affected. Usually, there is only one tumor in that kidney, but in a small number of cases, there is more than one tumor in the same kidney. In about 5-10% of children with Wilms tumors, the cancer is bilateral, with tumors in both kidneys.

Generally, Wilms tumors grow rather large before they are detected. While the tumors are usually found before they metastasize (spread), they can spread to other organs – most often to the lungs and abdominal lymph nodes.

What are the risk factors of Wilms tumors?

Most of the time, no known cause can be identified for Wilms tumor. However, there are some known risk factors, such as:
  • Age: the average age for Wilms tumors is about 3-4 years old.
  • Race/ethnicity: African-American children have a slightly higher risk than white children. The lowest incidence is among Asian-American children.
  • Gender: girls are slightly more at risk than boys
  • Family history: about 1-2% of children with Wilms tumor have one or more relatives with the same cancer.
  • Genetic syndromes: there is a strong association with certain kinds of hereditary syndromes (some of which are very rare). The syndromes linked to Wilms tumor include:
  • - WAGR syndrome
  • - Denys-Drash syndrome and Frasier syndrome
  • - Beckwith-Wiedemann syndrome
  • - Other syndromes are less strongly linked, such as Perlman syndrome, Sotos syndrome, Simpson-Golabi-Behmel syndrome, Bloom syndrome, Li-Fraumeni syndrome, and Trisomy 18
  • Birth defects: specific birth defects that are not associated with a genetic syndrome also put children at a higher risk of Wilms tumor, including aniridia, hemihypertrophy, cryptorchidism, and hypospadias.

What are the symptoms of Wilms tumors?

Wilms tumors can grow very large before causing any symptoms, and children may act normally and look healthy during this time. Once symptoms present, the most common signs of Wilms tumor are:

  • Swelling or a large lump in the abdomen; may or may not be painful
  • Nausea
  • Shortness of breath
  • Blood in the urine
  • Fever
  • Loss of appetite
  • Constipation
  • High blood pressure

What many types of Wilms tumors are there?

There are two major types of Wilms tumors, classified primarily by their histology, which is how they appear under a microscope.

  1. Favorable histology: the cancer cells don’t look normal, but the cells’ nuclei are not overly large or distorted. This type of Wilms tumor is much more common, and treatment generally leads to a favorable outcome.
  2. Anaplastic histology: the appearance of the cancer cells varies widely, and the nuclei are usually very large and distorted (called anaplasia). Diffuse anaplasia refers to when it is spread throughout the tumor, whereas focal anaplasia is when the distorted cells are limited to certain parts of the tumor.

In addition to these two classifications of Wilms tumor, the stage of the disease (how far it has spread) is also significant. According to guidelines from the Children’s Oncology Group (COG), Wilms tumor is staged as follows:

  • Stage I: about 20% of all cases; the tumor is located only in the kidney and can be entirely removed surgically.
  • Stage II: about 22% of all cases; the tumor spreads beyond the kidney but can be entirely removed surgically.
  • Stage III: about 32% of all cases; the tumor is limited to the abdomen but cannot be entirely removed surgically.
  • Stage IV: about 20% of all cases; the disease has spread into the bloodstream and may be found in other body organs, typically the liver or lung.
  • Stage V: about 6% of all cases; at diagnosis, the tumor is located on both kidneys (bilateral).

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Sheba Medical Center provides innovative, personalized medical care to patients from around the world. We are the largest, most comprehensive hospital in the Middle East and dedicated to providing advanced and compassionate medicine for everyone. We welcome all cases, including the rarest and the most challenging. Our medical teams collaborate to provide the best possible health outcomes. From your initial inquiry through the long-term follow-up care, we are here for you.

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