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Cancer is a deadly disease that is characterized by the development of a tumor due to abnormal and uncontrolled cell division. Though this disease could be linked to the poor lifestyle choices (alcoholism, smoking, substance abuse, etc.) in case of adults, the causes of cancer in children are largely unknown. Though a child might be a risk of developing a specific type of carcinoma due to DNA or genetic mutations that he/she inherits from a parent, it is mostly the acquired DNA changes that occur early in life or before birth that cause cancer in children. Some of the suspected causes include exposure to ionizing radiation and genetic or chromosomal abnormalities.

According to the American Cancer Society (ACS), childhood cancers make up less than 1% of all cancers diagnosed each year. However, the rates of cancer in children have been rising in the past few decades. As per the statistics provided by ACS, about 10,450 children in the United States under the age of 15 will be diagnosed with cancer in 2014. Unfortunately, around 1,350 children under the age of 15 years are expected to die from cancer in 2014.

International Classification of Childhood Cancers

There are 12 major categories that are classified according to their histology. These include:

» Leukemias
» Lymphomas and reticuloendothelial neoplasms
» CNS and miscellaneous intracranial and intraspinal neoplasms
» Neuroblastoma and other peripheral nerve cell tumors
» Retinoblastoma
» Renal tumors
» Hepatic tumors
» Malignant bone tumors
» Soft tissue and other extraosseous sarcomas
» Germ cell tumors, trophoblastic tumors, and neoplasms of gonads
» Other malignant epithelial neoplasms and malignant melanomas
» Other and unspecified malignant neoplasms

Types of Cancers that Commonly Affect Children

The common types of carcinomas that affect children are leukemia, brain tumors, and lymphoma (Hodgkin's and non-Hodgkin's lymphoma). Here's some information about them:

♦ Leukemia
Cancer of the bone marrow or blood is known as leukemia. It is the most common type of carcinoma affecting children. It occurs when the immature white blood cells become cancerous and tend to divide and grow rapidly. Soon, the number of the abnormal lymphoblasts outnumber the normal red blood cells, platelets, and white blood cells. There are two types of leukemia:

Acute Lymphoblastic Leukemia (ALL)
About 75% of children affected by leukemia have acute lymphoblastic leukemia. It is a cancer of the immature lymphoid cells in the bone marrow.

Acute Myelogenous Leukemia (AML)
Also known as acute nonlymphocytic leukemia (ANLL), this is a carcinoma of the immature myeloid blood cells in the bone marrow. It can affect children of any age.

♦ Cancer of the Central Nervous System
The central nervous system (CNS) consists of the brain and spinal cord. There are different types of CNS tumors that cause about 17% of carcinomas occurring in people under the age of 20 years. Majority of the CNS cancers that affect children and adolescents are the cancers of the astrocytes in the brain, that is, gliomas or astrocytomas. Medulloblastomas refer to fast-growing aggressive tumors occurring in the cerebellum. Other common brain tumors include brainstem gliomas, ependymomas, and optic nerve gliomas.

♦ Sarcomas
Sarcomas include bone cancers and soft tissue sarcomas. The common sarcomas that affect children include:

Bone Cancers
The types of bone cancers that affect children are as follows:

→ Osteosarcoma
The most common type of bone cancer is osteosarcoma. These tumors are mostly located at metaphysis, which are the broad ends of long bones. It occurs in the age group of 15 to 25 years.

→ Ewing's Sarcoma
Ewing's sarcoma can affect any bone, but generally begins with tumors in the long bones. It then spreads to various other bones and organs. It mostly affects adolescents and accounts for about 2% of all cancers in children.

Soft Tissue Sarcoma
One of the common types of soft tissue sarcoma is rhabdomyosarcoma. It usually begins in the embryonic cells that develop into skeletal muscles. It may occur anywhere in the body like head, neck, groin, abdomen, arms, legs, pelvis, etc. The patient complains of pain and swelling of the affected part. It accounts for about 3% of all cancer types that affect children.

♦ Lymphomas
Lymphomas include carcinomas originating in the lymphoid tissues of the lymph nodes, spleen, liver, and bone marrow. These account for about 15% of carcinomas affecting people under the age of 20. Lymphoma is divided into two broad categories: Hodgkin's and non-Hodgkin's lymphoma (NHL).

Hodgkin's Lymphoma
Also known as Hodgkin's disease, it is characterized by the presence of specialized, giant abnormal cells called Reed-Sternberg cells. It is common in teenagers and young adults and is associated with viral infections.

Non-Hodgkin's Lymphoma
The lymphomas that show an absence of Reed-Sternberg cells are classified as non-Hodgkin's lymphomas and are associated with immune system deficiencies. These include Burkitt's lymphoma, non-Burkitt's lymphoma, and lymphoblastic lymphoma..

♦ Cancer of the Liver
There are two types of liver cancers that can occur in children. These include hepatoblastoma and hepatocellular carcinoma. Hepatoblastomas are very common in children under 3 years of age. Hepatocellular carcinomas are less common and are found in children under 4 years of age, as well as those between the age group of 12 to 15 years.

♦ Cancer of the Kidney
Wilm's tumor (also called nephroblastoma) is a type of kidney cancer that affects children under the age of 5 as well as older children in some cases. It mostly affects one kidney, and is said to be hereditary in a few cases. Other kidney cancers that affect children include malignant rhabdoid tumors and clear cell sarcoma of kidney.

Neuroblastoma
This cancer develops in the nerve cells of infants and very young children. It is often diagnosed within the first 5 years of age. It usually originates from the adrenal glands or spinal cord and then spreads to the bones, bone marrow, and other organs. It accounts for about 7% of all childhood cancers.

Retinoblastoma
Retinoblastoma implies the formation of cancerous tumors in the retina. It accounts for less than 3% of cancers that affect children. It usually affects children under the age of 6 years and is most commonly diagnosed within the first 2 years of age. The pupils of the eyes appear white or distorted due to presence of the tumor, thus indicating the occurrence of retinoblastoma in the child.

Cancer can damage a child's organs and bones, and weaken the immune system. However, if it is detected early, the prognosis can be better in some of the types. However, it is still the second leading cause of death in children after accidents. Currently, around 80% of children with cancer survive 5 years or more in comparison to mid-1970s, where only 60% of the children affected by this disease survived 5 years or more. This is due to the advancements in the field of medical science. The usual treatment options include chemotherapy, radiation therapy, and surgery.

Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.