ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Childhood Cancer. Use the menu to see other pages. Think of that menu as a roadmap for this entire guide.

Cancer is uncommon in children. Most cancers (99%) develop in adults, and it is most common in older adults. About 1 out of every 3 adults will develop cancer during their lifetime, while about 1 in 285 children will develop cancer before the age of 20.

At the same time, there is a lot of research going on to discover new treatments for childhood cancers. This research has greatly improved the overall survival rate for children with cancer, which is now more than 80%.

What is childhood cancer?

Cancer in children can occur anywhere in the body, including the blood and lymph node 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 (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

    • Pleomorphioc 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%), 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 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 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 (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%)

Looking for More of an Introduction?

If you would like more of an introduction, explore these related items. Please note that these links will take you to other sections on Cancer.Net:

• Cancer.Net Patient Education Videos: The Moving Forward series, in collaboration with The Livestrong Foundation, provides perspectives from both doctors and survivors on topics often faced by teenagers and young adults living with cancer.

• Find a Cancer Doctor. Search for a cancer specialist in your local area using this free database of doctors from the American Society of Clinical Oncology (ASCO).

• Cancer Terms. Learn what medical phrases and terms used in cancer care and treatment mean.

The next section in this guide is Statistics. It helps explain the number of people under age 20 who are diagnosed with cancer and general survival rates. Use the menu to choose a different section to read in this guide.