How Does Kidney Cancer Affect Children?

The kidneys are two bean-shaped organs that are found in the upper back part of the abdomen. Their function is to filter waste as well as excess salt and water from your blood. These filtered substances eventually become urine.

Kidney cancer is cancer that starts in the kidneys. It happens when cells in the kidneys begin to grow and divide out of control.

Kidney cancer can happen in children. According to the National Cancer Institute (NCI), it’s one of the most common cancers to affect children between 0 and 14 years.

Nevertheless, other types of cancer are still more common in children. Researchers have estimated that kidney cancer makes up roughly 5% of all cancers that happen prior to age 15.

The most common type of kidney cancer in children is Wilms’ tumor, or nephroblastoma. According to the ACS, almost 9 out of 10 kidney cancers in children are Wilms’ tumors.

Wilms’ tumors typically develop between the ages of 3 and 5 years. They often only affect one kidney (unilateral), but in rarer cases can affect both kidneys (bilateral).

Most Wilms’ tumors have grown to be very large by the time of diagnosis. They’re often felt as a mass in the abdomen and may be first noticed when a parent is bathing or dressing a child.

Other types of kidney cancers are less common in children, but can still occur. Some examples include:

• Mesoblastic nephroma: This type is often diagnosed in the first 3 months of life.
• Renal cell carcinoma: Renal cell carcinoma is the most common type of kidney cancer in adults and happens more often than Wilms’ tumors in older teens.
• Malignant rhabdoid tumor of the kidney: This is an aggressive type of cancer that most often affects infants and toddlers.
• Clear cell sarcoma of the kidney: This type has a similar age at diagnosis as Wilms’ tumors but spreads more easily.

Some of the potential signs of kidney cancer in children include:

• a lump in the abdomen that can be felt through the skin
• abdominal pain
• blood in the urine
• constipation
• loss of appetite
• unexplained weight loss
• high blood pressure

Cancer happens when cells in the body have changes in their DNA that cause them to grow and divide out of control. It’s still unknown what exactly causes these changes to happen in children with kidney cancer.

Researchers have identified several genetic changes associated with kidney cancers in children. However, not all children with kidney cancer have these changes. Overall, more research is needed into the cause of kidney cancer in children.

In order to diagnose kidney cancer, your child’s doctor will first do a physical exam and get your child’s medical history.

Blood and urine tests

If they suspect a kidney problem, they’ll order blood and urine tests, such as:

• Urinalysis: Urinalysis evaluates a urine sample’s color and also tests it for the presence of blood, protein, or bacteria.
• Renal function tests: Renal function tests are blood or urine tests that assess substances associated with how well the kidneys are working.
• Complete blood count: Complete blood count is a blood test that measures the levels of the different types of blood cells.
• Metabolic panel: Metabolic panel is a blood test that gives a doctor an idea of a person’s overall health, including the function of their liver and kidneys.

Imaging tests

Various imaging tests can also be used to further assess a lump or mass around the kidneys. These can include:

• Ultrasound: Ultrasound is typically the first type of imaging used.
• Computed tomography (CT) scan: CT scans use X-rays and a computer to produce images of inside the body.
• Magnetic resonance imaging (MRI) scan: MRI scans use radio waves and magnets to create images of inside the body.
• Chest X-ray: Chest X-ray is generally used to see if cancer has spread to the lungs.

Biopsy

A biopsy may also be done, which is when a small tissue sample is removed from a tumor. A doctor can look at this sample under a microscope to confirm the type of cancer as well as characteristics of the tumor that can affect outlook.

Surgery is a common treatment for kidney cancer in children. When part or all of a kidney is removed, it’s called a nephrectomy.

Many times, Wilms’ tumors and other childhood kidney cancers are treated using a radical nephrectomy. This is when the entire kidney, including the tumor, is removed. Nearby lymph nodes may be removed as well.

A partial nephrectomy is the removal of the tumor and some of the surrounding kidney tissue. It may be done if the cancer affects both kidneys. Its aim is to get rid of the cancer and preserve as much kidney function as possible.

Radiation therapy and chemotherapy may also be used for treating kidney cancer in children. These treatments may be recommended:

• before surgery to help shrink a tumor (neoadjuvant therapy)
• after surgery to help get rid of any remaining cancer cells (adjuvant therapy)
• when surgery isn’t recommended as a treatment option
• if the cancer has come back (recurred) or spread to other areas of the body (metastasized)

It’s also possible that targeted therapy or immunotherapy may be used, depending on the specific type of cancer and its stage.

Since some kidney cancers in children are quite rare, a doctor may also suggest getting treatment through a clinical trial. Clinical trials are used to evaluate the safety and effectiveness of new kidney cancer treatments.

Some of the potential risk factors of kidney cancer in children are:

• having a family history of kidney cancer or childhood kidney cancer
• having certain genetic conditions, including:
  • Beckwith-Wiedemann syndrome
  • Denys-Drash syndrome
  • Frasier syndrome
  • tuberous sclerosis
  • Von Hippel-Lindau disease
  • WAGR syndrome
• having certain urinary tract abnormalities like hypospadias or undescended testicles
• being exposed to pesticides while in the womb
• undergoing previous treatment with chemotherapy or radiation therapy

Remember to keep in mind that having risk factors doesn’t mean that a child will certainly develop kidney cancer. It just means that they’re at an increased risk compared with children who don’t have risk factors.

The outlook for kidney cancer in children can depend on many factors, including:

• the specific type of kidney cancer
• the extent (stage) of the kidney cancer
• the response of the cancer to the recommended treatment
• the presence of certain genetic changes
• whether the cancer is newly diagnosed or has recurred
• the age and overall health of the child

Wilms’ tumor, the most common type of childhood kidney cancer, is grouped into two types based on how the cancer looks under the microscope:

• Anaplastic histology: Kidney cancer is said to have anaplastic histology when the cancer cells are varIous sizes and the nucleus (the part that contains DNA) of these cells is very large. There are two types of anaplastic histology:
  • Diffuse anaplasia: Anaplastic cells are found throughout the tumor.
  • Focal anaplasia: Anaplastic cells are found in one location within the tumor.
• Favorable histology: Kidney cancer is said to have favorable histology when the cancer cells aren’t anaplastic.

The outlook for anaplastic tumors isn’t as good, with survival rates ranging between 38% and 84%.

Non-Wilms’ tumors have a more variable outlook. A 2020 study of 109 children with non-Wilms’ tumors found that overall 3-year survival for the entire group was 59%.

Of all the non-Wilms’ kidney cancers included, malignant rhabdoid tumors and recurrent non-Wilms’ tumors had the worst outcomes. However, the survival for low risk tumors like mesoblastic nephroma was 100%.

We’ll try to answer any additional questions that you may have about kidney cancer in children below.

Can kidney cancer in children be prevented?

While adults can help to prevent many types of cancers through lifestyle changes, there’s no known way to prevent most childhood cancers, including kidney cancers.

Additionally, most of the things that boost a child’s risk for kidney cancer involve factors that can’t be changed. These include genetics or congenital conditions.

Is kidney cancer different in adults?

Adults typically get different types of kidney cancers than children. For example, 9 out of 10 kidney cancers in adults are renal cell carcinomas.

Further, more adults get kidney cancer each year. The ACS estimates that there will be 79,000 new diagnoses of kidney cancer in the United States in 2022.

There are similarities in treatment, though. For example, surgery is often the preferred initial method of treatment for kidney cancer in both adults and children.

Can kidney cancer spread to other areas of the body?

Yes. According to the American Urological Association, the most common place for kidney cancer to spread to in children is the lungs. It may also commonly spread to the bones or brain.

Can kidney cancer recur in children?

Yes, it’s possible for some kidney cancers to come back after treatment. Recurrence can happen in the kidneys or in another part of the body like the lungs or liver.

What other cancers are common in children?

In addition to kidney cancer, other types of cancer that are common in children include:

• leukemias
• lymphomas
• neuroblastoma
• bone tumors
• brain and central nervous system tumors

Overall, cancer in children is rare. When children do get cancer, certain types are more common. One of these is kidney cancer.

The overwhelming majority of kidney cancers in children are Wilms’ tumors. Other types of kidney cancer can happen but are much less common.

Most of the time, the treatment of kidney cancer involves surgery to remove the tumor and often the entire kidney. It’s also possible that chemotherapy or radiation therapy may be used as well.

The outlook for most Wilms’ tumors is positive. However, the outlook for non-Wilms’ tumors may not be as good. If your child has received a diagnosis of kidney cancer, their care team can give you a better idea of their individual outlook.