In children, cancer is uncommon. While, most cancers, about 99%, develop in adults and are more common in older people. About 1 out of 285 children develop cancer before 20 years of age. The research has dramatically improved the overall survival rate for children with cancer, which is now more than 80%.
Moreover, cancer in children can begin anywhere in the body, including the brain and spinal cord (central nervous system), the blood and lymphatic systems, kidneys, and other organs and tissues.
However, there is no known cause behind childhood cancers. Childhood cancers can behave very differently from cancer in adults, even when they start in the same organ or tissue of the body.
Cancer starts when healthy cells change and grow out of control. In most cancer, these cells form a mass called a tumour. But this tumour can be cancerous or benign. While, cancerous tumour is malignant, meaning it can grow and spread to other parts of the body. A benign tumour means the tumour can grow but will not spread to distant parts of the body.
Types of Childhood Cancers
‘Childhood cancer,’ also known as pediatric cancer, is a term used to describe various cancer types found in children. Below-mentioned are generally most common types of cancer diagnosed in children under age 15:
- Leukemia (accounts for about 29% of childhood cancer cases)
- Acute lymphoblastic leukemia (ALL)
- Acute myeloid leukemia (AML)
- Brain and spinal cord tumours (26%), also called central nervous system (CNS) tumours.
- Glial tumours
- Choroid plexus carcinoma
- Mixed glial neuronal tumours
- Desmoplastic infantile ganglioglioma
- Pleomorphic xanthoastrocytoma
- Anaplastic ganglioglioma
- Neural tumours
- Embryonal tumours
- Atypical Teratoid/Rhabdoid tumour
- Pineal tumours
- Neuroblastoma (6%) is a tumour of immature nerve cells. The tumour often starts in the adrenal glands, located on top of the kidneys and are part of the body’s endocrine (hormonal) system.
- Wilms tumour (5%), a type of kidney tumour
- Non-Hodgkin lymphoma(5%) and Hodgkin lymphoma (3%), cancers that start in the lymph system
- Rhabdomyosarcoma (3%), a type of tumour that most commonly starts in the striated skeletal muscles. Non-rhabdomyosarcoma soft tissue sarcomas can also occur in other parts of the body.
- Retinoblastoma (2%), an eye tumour
- Osteosarcoma (2%) and Ewing sarcoma (1%), tumours that usually begin in or near the bone
- Germ cell tumours, rare tumours that begin in the testicles of boys or ovaries of girls. Rarely, these tumours can start in other places in the body, including the brain.
- Pleuropulmonary blastoma, a rare type of lung cancer
- Hepatocellular carcinoma and hepatoblastoma, types of liver tumours
Cancer in Teenagers and Young Adults
There is more research regarding cancer in children diagnosed after 14. Since these children are starting to enter young adulthood, they may have unique medical, emotional, and social needs different from younger children having cancer.
Hence, teenagers and young adults with cancer should be treated at a pediatric oncology centre. While, ideally, they should be treated at a centre where medical oncologists, doctors who treat cancer in adults, and pediatric oncologists, who treat childhood cancer, work together to plan treatment. Furthermore, this ensures that they receive the newest treatments and are cared for by a team of doctors familiar with these diseases. This is especially important for teenagers with lymphoma, leukemia, or a bone tumour. Treatment by specialists friendly with these diseases has generally shown to improve survival.
Some patients within the AYA group have types of cancer more commonly found in adults, such as melanoma, testicular cancer, or ovarian cancer. Teenagers with these cancers may receive treatments similar to adults but need age-appropriate support for their emotional and social needs. And so, consult with the health care team about available support programs.
Most common types of cancer in teenagers
- Hodgkin lymphoma (15%)
- Thyroid cancer (11%)
- Central nervous system tumours (10%)
- Acute lymphoblastic leukemia (ALL) (8%)
- Non-Hodgkin lymphoma (8%)
- Germ cell tumours, including testicular cancer (8%) and ovarian cancer (2%)
- Soft tissue sarcoma (7%)
- Bone tumours (7%), including osteosarcoma and Ewing sarcoma
- Melanoma (6%)
- Acute myeloid leukaemia (AML) (4%)