Childhood Cancer

What is childhood cancer?

Cancer in children can occur anywhere in the body, including the blood and lymphatic systems, brain and spinal cord (central nervous system, or CNS), kidneys, bones, and other organs and tissues.

Most of the time, there are no known causes for childhood cancers. Childhood cancers may behave very differently from adult cancers, even when they start in the same part of the body.

Cancer begins when healthy cells change and grow out of control. In most types of cancer, these cells form a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread to distant parts of the body. Malignant tumors also grow rapidly, whereas benign tumors generally grow slowly.

In leukemia, a cancer of the blood that starts in the bone marrow, these abnormal cells very rarely form a solid tumor. Instead, these cells crowd out other types of cells in the bone marrow. This prevents the production of:

• Normal red blood cells. Cells that carry oxygen to tissues.
• White blood cells. Cells that fight infection.
• Platelets. The part of the blood needed for clotting.

Types of childhood cancer

“Childhood cancer,” also called pediatric cancer, is a general term used to describe a range of cancer types found in children. Below are the most common types of cancer diagnosed in children under age 15:

• Leukemia (which accounts for about 28% of childhood cancer cases)
  • Acute lymphoblastic leukemia (ALL)
  • Acute myeloid leukemia (AML)
• Brain and spinal cord tumors (27%), also called CNS tumors
  • Glial tumors
    • Astrocytoma
    • Oligodendroglioma
    • Ependymoma
    • Choroid plexus carcinoma
    • Oligoastrocytoma
    • Glioblastoma
  • Mixed glial neuronal tumors
    • Ganglioglioma
    • Desmoplastic infantile ganglioglioma
    • Pleomorphic xanthoastrocytoma
    • Anaplastic ganglioglioma
  • Neural tumors
    • Gangliocytoma
    • Neurocytoma
  • Embryonal tumors
    • Medulloblastoma
    • Medulloepithelioma
  • Ependymoblastoma
    • Atypical Teratoid/Rhabdoid tumor
  • Pineal tumors
    • Pineocytoma
• Neuroblastoma (6%), a tumor of immature nerve cells. The tumor often starts in the adrenal glands, which are located on top of the kidneys and are part of the body’s endocrine (hormonal) system.
• Non-Hodgkin lymphoma (6%) and Hodgkin lymphoma (3%), cancers that begin in the lymph system
• Wilms tumor (5%), a type of kidney tumor
• Rhabdomyosarcoma (3%), a type of tumor that most commonly begins in the striated skeletal muscles. Non-rhabdomyosarcoma soft tissue sarcomas can also occur in other parts of the body.
• Germ cell tumors (3%) are rare tumors that begin in the testicles of boys or ovaries of girls. Rarely, these tumors can begin in other places in the body, including the brain.
• Retinoblastoma (2%), a type of eye tumor
• Osteosarcoma (2%) and Ewing sarcoma (1%), tumors that usually begin in or near the bone
• Pleuropulmonary blastoma, a rare kind of lung cancer
• Hepatoblastoma and hepatocellular carcinoma (1%), types of liver tumors

Cancer in teenagers and young adults

Research is increasing in children diagnosed with cancer after the age of 14. Since these children are starting to enter young adulthood, they may have unique medical, social, and emotional needs that are different from those of younger children with cancer. They are part of a group often called adolescents and young adults (AYA).

Teenagers and young adults with cancer should most often be treated at a pediatric oncology center. Ideally, they should be treated at a center where both medical oncologists, which are doctors who treat cancer in adults, and pediatric oncologists, which are doctors who treat cancer in children, work together to plan treatment. This collaboration will ensure that they receive the newest treatments and are cared for by a team of doctors familiar with these diseases. Collaboration is especially important for teenagers who have lymphoma, leukemia, or a bone tumor. Treatment by specialists familiar with these diseases has been shown to improve survival.

Within the AYA group, there are also patients who have types of cancer more commonly found in adults, such as melanoma, testicular cancer, or ovarian cancer. Teenagers with these cancers may receive treatments that are similar to those of adults, but they also need age-appropriate support for their social and emotional needs. Talk with your health care team about what support programs are available.

Below are the most common types of cancer in teenagers, ages 15 to 19:

• Central nervous system (CNS) tumors (which account for about 21% of cancer cases in teenagers)
• Hodgkin lymphoma (12%)
• Thyroid cancer (12%)
• Germ cell tumors, including testicular cancer (8%) and ovarian cancer (2%)
• Non-Hodgkin lymphoma (7%)
• Soft tissue sarcoma (7%)
• Acute lymphoblastic leukemia (ALL) (6%)
• Bone tumors (5%), including osteosarcoma and Ewing sarcoma
• Acute myeloid leukemia (AML) (4%)
• Melanoma (3%)

How many children and teens are diagnosed with childhood cancer?

In general, cancer in children and teens is uncommon.

In 2023, an estimated 9,910 children younger than 15 and about 5,280 teens ages 15 to 19 in the United States will be diagnosed with cancer.

In children under 15, leukemia makes up 28% of all childhood cancers diagnosed. The next most common type of childhood cancer is brain cancer (26%), followed by lymphoma (12%).

In teens ages 15 to 19, brain cancer (21%), lymphoma (19%), and leukemia (13%) are the most commonly diagnosed cancers. Some cancers that are often found in adults are also common in teens. For example, thyroid cancer makes up 12% of cancer cases in teens, while melanoma makes up 3% of cases in this age group.

Rates of cancer in children and teens have slowly increased since 1975, but they stabilized between 2010 and 2019. However, rates in teens continue to increase by around 1% each year. Most children and teens diagnosed with cancer can be treated successfully. Between 1970 and 2020, the number of deaths from cancer in children and teens decreased by more than 50%. This is likely due to increased participation in clinical trials and advances in treatment.

Cancer is the top disease-related cause of death for children and teens in the United States. After accidents, cancer remains the second-leading cause of death in children under age 15. Cancer is also the fourth leading cause of death in teens ages 15 to 19, after accidents, suicide, and homicide.

It is estimated that 1,040 deaths from cancer will occur in the United States this year in children younger than 15. An estimated 550 deaths from cancer will occur in teens ages 15 to 19.

What are the risk factors for childhood cancer?

A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several known risk factors never develop cancer, while others with no known risk factors do.

Doctors and researchers don’t know what causes most childhood cancers. A small percentage of cancers can be linked to genetic disorders such as Down syndrome, other inherited disorders, or prior radiation exposure. Environmental causes, such as exposure to infectious and toxic substances, are unlikely to cause childhood cancer.

To help doctors learn more about risk factors, the Children’s Oncology Group (COG) coordinates a large childhood cancer registry. (Please note that this link takes you to a separate website.) Once registered with the network, patients and families may be asked if doctors and researchers can contact them in the future to collect information for studies on genetic and environmental factors that may be connected to the development of childhood cancers. Research continues in this area.

What are the symptoms and signs of childhood cancer?

Cancer can be hard to detect in children. Children with cancer may experience one or more of the symptoms or signs described below, many of which are similar to common childhood illnesses. Symptoms are changes that you can feel in your body. Signs are changes in something measured, like taking your blood pressure or doing a lab test. Together, symptoms and signs can help describe a medical problem. Sometimes, children with cancer do not have any of the symptoms and signs described below. Or, the cause of a symptom or sign may be a medical condition that is not cancer.

Many of the symptoms can be described using an acronym (CHILD CANCER) provided by The Pediatric Oncology Resource Center.

• Continued, unexplained weight loss
• Headaches, often with early morning vomiting
• Increased swelling or persistent pain in the bones, joints, back, or legs
• Lump or mass, especially in the abdomen, neck, chest, pelvis, or armpits
• Development of excessive bruising, bleeding, or rash
• Constant, frequent, or persistent infections
• A whitish color behind the pupil
• Nausea that persists or vomiting without nausea
• Constant tiredness or noticeable paleness
• Eye or vision changes that occur suddenly and persist
• Recurring or persistent fevers of unknown origin

If you are concerned about any changes in your child, please talk with your family doctor. Your child’s doctor will try to understand what is causing your child’s symptom(s). They may do an exam and order tests to understand the cause of the problem, which is called a diagnosis.

If cancer is diagnosed, relieving symptoms remains an important part of cancer care and treatment. Managing symptoms may also be called “palliative and supportive care,” which is not the same as hospice care given at the end of life. You can receive palliative and supportive care at any time during cancer treatment. This type of care focuses on managing symptoms and supporting people who face serious illnesses, such as cancer. Learn more in this guide’s section on Coping with Treatment.

Be sure to talk with your child’s health care team about the symptoms your child experiences, including any new symptoms or a change in symptoms.